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Surfactant Formulations to Enhance Triclopyr Amine Efficacy: Effects on Adhesion, Retention and Contact Phytotoxicity On Three Hardwood SpeciesForster, W. Alison II 13 November 1998 (has links)
Loblolly pine (Pinus taeda L) is the leading Southern (USA) pine, in terms of acres planted (Fortson et al.,1996). Since commercial forest acreage is predicted to remain fairly constant over the next 50 years, productivity must be increased if the South is going to meet a larger share of the nation's timber supply needs (Gjerstad and Barber, 1987). Hardwoods have been shown to have a consistent negative growth impact on pines, and uncontrolled hardwoods continue to compete aggressively with pines throughout a rotation, especially when hardwoods remain in the pine canopy.
Competing vegetation can be efficiently controlled by herbicides, which need to be formulated either in-can or in-tank to allow them to perform optimally. Adjuvants have proven essential to increasing the efficacy of herbicides, due to their ability to consistently improve the performance of the basic pesticide product. There are, broadly speaking, two routes by which adjuvants can do this. The first is the minimization of off target deposition and second, by the maximization of the herbicidal effect once it is placed on the target ( Reeves, 1989). The major contributors to off- target deposition and retention are drift, in-flight volatilization, droplet shatter, bounce or runoff, washoff, and removal by wind. These losses result in pesticides never reaching the target or achieving only transitory deposition. There are two basic methods of maximizing the effect of the pesticide once it is on the target. The first is to improve coverage by the spray solution, which can be accomplished by lowering the surface tension of the spray with surfactant materials. The second is by improving the penetration or uptake into the target. Organosilicone surfactants can reduce the surface tension of aqueous pesticides far below that which is possible with nonsilicone surfactants, resulting in efficient wetting of even the most hydrophobic leaf surfaces. Additionally, by virtue of their low surface tension, these adjuvants can significantly increase the uptake of active chemicals directly into the plant via stomatal infiltration ( Stevens et al., 1991).
Triclopyr ([(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid) has been found to be an effective herbicide for hardwood control. Its two commercial formulations, a triethylamine (TEA) salt (Garlon 3A) and a butoxyethyl ester ( Garlon 4 ), vary considerably in their acceptability. The current ester formulation has two undesirable characteristics. One is that all ester formulations, regardless of chain length, have some volatility which is usually more than that of water-soluble salts. The second is that the current ester formulation utilizes a kerosene solvent which is known to cause rapid foliar necrosis (possibly inhibiting herbicide translocation) and is a suspected carcinogen ( Zedaker et al., 1995). In most applications, the ester formulation has been more efficacious than the amine formulation on both an equal active ingredient basis and on an equal cost basis. Research had demonstrated a potential to enhance the uptake of triclopyr through the use of organosilicones; however, significant problems still existed. It was found that the commercial TEA formulation of triclopyr (Garlon 3A) was "antagonistic" to the organosilicone surfactant Silwet L-77. To take full advantage of the properties of organosilicones, the antagonistic co-formulants of Garlon 3A needed to be removed or replaced, the best surfactant formulation identified, and a cost-effective concentration of the surfactant(s) needed to be found.
To do this adequately required that both physico-chemical processes and biological processes be studied. The relevant physico-chemical processes involved in a formulation's effect on spray impaction on the target plant include adhesion, reflection, retention and run-off. The important biological processes include the uptake and translocation of the herbicide into the plant.
The objectives of this study were: to evaluate the influence of formulation, active ingredient concentration, droplet size and leaf surface (adaxial vs. abaxial) on contact phytotoxicity, adhesion and retention to Acer rubrum, Liquidambar styraciflua and Quercus rubra by triclopyr formulations containing organosilicone surfactants and mixtures of silicone plus conventional surfactants. The adhesion and retention studies also evaluated the influence of leaf angle. Further objectives were to evaluate the influence of formulation and active ingredient concentration on spray retention by the adaxial and abaxial leaf surface of the selected species under field and track-sprayer conditions and to determine whether leaf characteristics (wax character and leaf angle ) could explain adhesion / retention.
Garlon 4, Garlon 3A and Triclopyr TEA + sequestrant (each at 0.32%, 1.6% and 3.2% ae) plus various concentrations of the surfactants Polyglycol 26-2, Rhodasurf DA-630, Surfadone LP-100, Silwet L-77 and Silwet 408, were tested for contact phytotoxicity, adhesion and retention on the adaxial and abaxial leaf surfaces of sweetgum, red oak and red maple.
Little or no contact phytotoxicity was observed with any formulation applied to the adaxial surface within 6 hours; some phytotoxicity was noted within 24 hours. Abaxial surface treatments showed much greater contact phytotoxicity. Contact phytotoxicity was caused by (1) increasing concentrations of stock triclopyr products, and (2) the influence of the organosilicone surfactants. However, these results were very species dependent. Conclusions made from the contact phytotoxicity study were: if the droplet size becomes too big, then efficacy will be reduced; increasing the concentration of active ingredient above a certain limit will not increase efficacy, and may in fact reduce it; the addition of the organosilicone surfactants Silwet L-77 and Silwet 408 delayed and reduced phytotoxicity in red oak ( the most susceptible species to contact phytotoxicity), and to a lesser extent in red maple, but increased the rate in sweetgum.
Major influences on adhesion were: droplet size ( increasing droplet size decreased adhesion); adaxial/abaxial leaf surface (abaxial adhesion less than adaxial); product concentration (increasing product concentration increased adhesion); leaf angle (increasing leaf angle decreased adhesion); and addition of surfactants (variable adhesion).
All new formulations gave greater adhesion than the commercial formulations, with Triclopyr TEA plus sequestrant plus n-octyl pyrrolidone plus Silwet 408 giving, overall, the greatest adhesion. Increasing product concentration gave greater adhesion. Increasing droplet size and angle of impact reduced adhesion. The adaxial leaf surface showed higher adhesion than the abaxial leaf surface. Adhesion was higher on sweetgum, followed by red oak, with red maple being the most difficult species to get formulations to adhere to.
Whereas increasing product concentration improves adhesion, the lowest contact phytotoxicity result would be from lowering product concentration. Looking at both sets of results, the best product concentration of those studied would then be 1.6% ae as this can provide high adhesion, while still enabling us to choose a formulation which gives minimal contact phytotoxicity.
In the laboratory, formulation had no significant effect on retention. However, there are other considerations which affect retention that need to be kept in mind. It was observed that droplets containing organosilicone could impact an already wetted surface and still adhere or be retained, whereas those droplets not containing any organosilicone surfactant would bounce quite a distance on impact with a pre-wetted surface. Impaction with an already wetted surface was not part of this study, and therefore was not studied quantitatively. Also, formulations containing organosilicone surfactants provide greater "wrap-around" to the lower surface ( Forster and Zabkiewicz, 1998), which is of great benefit when stomata are only on the abaxial surface, as is the case with these species.
Concentration and leaf angle also had no significant effect on retention. Droplet size was significant, with retention decreasing with increasing droplet size. Retention by the adaxial surface was significantly higher than retention by the abaxial surface. There was no significant difference overall between sweetgum and red oak, but retention by red maple was significantly lower.
Spray retention by the adaxial and abaxial leaf surfaces of the three tree species was also characterized in a field experiment conducted on a right of way site in North Anna, Virginia, USA. Amine ( Garlon 3A) formulations of triclopyr combined with Silwet 408, and the commercial triclopyr ester formulation, Garlon 4, were applied using a Radiarc sprayer equipped with 0.508 mm nozzles (approx. 1000 um droplets) applying 140 l/ha. The addition of the organosilicone surfactant Silwet 408 to the amine formulation gave the same total deposition as the commercial ester formulation, Garlon 4, while enhancing the abaxial retention as a percentage of total deposition. Thus the addition of organosilicone surfactant may have the ability to enhance herbicide uptake via the abaxial leaf surface, and therefore enhance efficacy. Field trial results showed that the alcohol ethoxylate, DA6, is not an essential component of the triclopyr amine / Silwet 408 formulation, in terms of retention.
The field trial application was also simulated on sweetgum, using a track-sprayer at the NZ Forest Research Institute Ltd. As in the field trial, the addition of Silwet 408 to triclopyr amine greatly enhanced abaxial retention as a percentage of total deposition, compared to that of Garlon 4. However, the track-sprayer results were very different from the field results, with amounts of adaxial and abaxial retention and total deposition much lower.
In agreement with published literature, it was found that the micro-roughness of the leaf surface can be used as a guide to explain adhesion results. The difference among trees in terms of leaf angles appeared to be much less important in explaining retention. / Master of Science
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Delineação de padrões na superfície da poliamida por processo de plasma / Delineation of patterns in the polyamide surface by plasma processHosokawa, Ricardo Shindi [UNESP] 17 November 2016 (has links)
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Previous issue date: 2016-11-17 / Neste trabalho foi investigada a possibilidade de se criar padrões regularmente distribuídos sobre a superfície da poliamida (PA), utilizando o processo de deposição de filmes em plasmas de baixa pressão. Para tal, um único procedimento foi empregado utilizando-se uma malha metálica comercial (60 μm) como máscara para delinear pilares na superfície da poliamida. Os plasmas de deposição foram gerados a partir de atmosferas contendo 70% de hexametildisiloxano (HMDSO) e 30% de oxigênio a uma pressão total de 23 Pa, já incluído o valor de 3 Pa referente à pressão de fundo. O plasma foi ativado pela aplicação do sinal de radiofrequência (13,56 MHz, 150 W) no suporte de amostras enquanto o eletrodo superior permaneceu aterrado. O tempo de deposição, t, foi alterado de 15 a 90 min. Na etapa inicial do trabalho o filme foi uniformemente depositado sobre o polímero sem a utilização de máscara. Uma segunda etapa de experimentos foi realizada, utilizando-se condições idênticas às anteriores, mas com o auxílio da trama metálica sobre as amostras para guiar a deposição do filme somente nos poros da máscara. Filmes organosilicones, compostos por estruturas granulares e com espessuras dependentes de t, foram uniformemente depositados sobre a PA quando a máscara não foi utilizada. A deposição do filme independentemente da condição de t, aumenta a rugosidade superficial e transforma a amostra inicialmente hidrofílica em hidrofóbica. Muito embora t afete de forma suave a composição química, estrutura molecular e a molhabilidade do filme, seu efeito na espessura da camada é substancial. Padrões na forma de pilares foram regularmente definidos na superfície da PA com a deposição do filme organosilicone e a utilização da máscara. A altura dos pilares cresce com t alcançando até 1 µm. Para os maiores valores de t empregados, as máscaras não atuaram efetivamente como sombra na região dos fios. Observou-se que a molhabilidade da superfície ficou estável com o tempo de envelhecimento e não foi afetada pelos padrões. / In this work it was investigated the possibility of creating patterns regularly distributed on the surface of the polyamide (PA), using the process of film deposition in low pressure plasmas. For such, a single procedure was employed using a commercial metallic mesh (60 μm) as a mask to delineate pillars on the polyamide surface. The depositing plasmas were generated from atmospheres containing 70% of hexamethyldisiloxane (HMDSO) and 30% of oxygen at a total pressure of 23 Pa, already included the amount of 3 Pa related to the background pressure. The plasma was activated applying a radiofrequency signal (13.56 MHz, 150 W) to the sample holder while grounding the topmost electrode. Deposition time, t, was changed from 15 to 90 min. In the initial stage of the work the film was evenly deposited on the polymer without the usage of mask. A second step of experiments was performed, using the same conditions as earlier, but with the aid of the metallic frame on the samples to guide the film deposition only in the pores of the mask. Organosilicones films consisting of granular structures and thickness dependent of t were evenly deposited on the PA when the mask was not used. The film deposition, independently of condition of t, increases the surface roughness and transforms the sample initially hydrophilic to hydrophobic. Although t affects smoothly the chemical composition, molecular structure and wettability of the film, its effect on the layer thickness is substantial. Patterns in the form of pillars were regularly defined on the surface of PA with the organosilicon film deposition and the usage of the mask. The height of the pillars grows with t reaching up to 1 micrometers. For higher values of t, the masks did not act effectively as shadow in the wire region. It was observed that the surface wettability was stable with the aging time and it was not affected by the patterns.
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Characterization of Organosilicone Surfactants and Their Effects on Sulfonylurea Herbicide ActivitySun, Jinxia 05 April 1996 (has links)
This research focused on the characterization of organosilicone surfactants and their effects on sulfonylurea herbicide activity. The project included efficacy tests, rainfastness studies in the greenhouse, radiotracer studies on herbicide uptake, fluorescent dye studies on surface deposition, and various measurements of physico-chemical properties.
In measuring physico-chemical properties, a logistic dose response relationship was found between adjuvant concentration and contact angle on parafilm. An AsymSigR relationship existed between adjuvant concentration and surface tension for all the adjuvants. The organosilicones, Silwet L-77, Silwet 408, and Sylgard 309, and Kinetic (a blend of an organosilicone with a nonionic surfactant) gave equilibrium surface tension values around 20 dyne/cm and showed great spreading ability on the foliage of velvetleaf. With the conventional adjuvants, Agri-Dex, methylated soybean oil, Rigo oil concentration, and X-77, and Dyne-Amic (a blend of an organosilicone with a crop oil concentrate), surface tension was rarely below 28 dyne/cm and spreading ability was limited on velvetleaf. In addition, the organosilicone surfactant and Kinetic also lowered dynamic surface tension, which may improve droplet retention on leaf surfaces. The differences in physico-chemical properties between Kinetic and Dyne-Amic confirmed that carefully electing a co-adjuvant for an organosilicone blend is critical to avoid antagonism with trisiloxane molecules and retain the unique physico-chemical properties of organosilicone in the blends.
Studies involving structurally-related organosilicones showed that the end structure in the trisiloxane hydrophilic group has little or no effect on surface tension, contact angle, spread pattern, herbicide uptake and translocation, and efficacy of primisulfuron on velvetleaf. It may be suggested that there is not a strict requirement to purify the end structure during the synthesis process, which is time consuming and expensive.
When 14C-primisulfuron was combined with organosilicones or the blends, the uptake of 14C at 1 or 2 h after herbicide application was significantly higher than when combined with conventional adjuvants in velvetleaf. In the greenhouse, organosilicone surfactants greatly increased the rainfastness of primisulfuron in velvetleaf. The effect was immediate and dramatic, even when simulated rainfall was applied 0.25 h after treatment. In addition, herbicide efficacy on marginally susceptible weed species, velvetleaf and barnyardgrass, was significantly increased. A very complicated relationship exists between herbicides and adjuvants. The enhancement effects of adjuvants are often herbicide specific, weed species specific, and even environment specific. No one type of adjuvant functions well in all circumstances. Therefore, there is a need to understand the properties and functions of each class of adjuvants and locate the 'right' niche for each individual adjuvant. / Ph. D.
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Diagnostika depozice tenkých vrstev připravovaných z tetravinylsilanu / Diagnostics of thin layer deposition using tetravinylsilane monomerFlamíková, Kristýna January 2010 (has links)
The aim of this work is plasma diagnostic during the deposition of thin films based on organosilicone compounds. These layers have a wide range of applications mainly as protective coatings or intermediate phase in composites reinforced by glass fibers. The theoretical part of this work gives a basic fundaments of optical emission spectroscopy and mass spectroscopy and describes procedures for rotational, vibrational, and electron temperature calculations. The RF capacitive coupled discharge in configuration with planar electrodes was used with tetravinylsilane (TVS) organosilicone monomer in this study. The optical emission spectroscopy and mass spectroscopy were applied for the plasma diagnostics. The deposition process was carried out in continuous regime with applied power of 20, 25, 40, 50, 60, and 70 W, some experiments were done also in pulsed regime with duty cycle 1:1, 1:4 and 1:9 at fixed power of 50 W and 10 W when discharge was on. The atomic lines of hydrogen Balmer series and many rotational lines of molecular hydrogen were identified in the spectra. Besides them, the molecular bands of SiH, CH and C2 species were observed. The rotational temperature calculated from 0-0 CH band was in the range of 600 – 1000 K depending on the discharge conditions. The electron temperature in the range of 3600-7500 K was calculated from hydrogen atomic lines. In situ mass spectra collected simultaneously with optical emission spectra showed TVS monomer fragmentation increase with the increase of applied power in continuous regime. This result well correlated with OES in case of CH radical and hydrogen species, the other particles were mainly non-measurable by emission spectroscopy. The same results were also obtained with respect to the duty cycle parameter. The presented results clearly demonstrated the increase of monomer fragmentation with the increase of mean applied discharge power. Determination of prepared layer properties is a subject of other works and their relation to the plasma parameters will be a subject of further studies.
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Oportunidades, demanda regulatória e de pesquisa e uso de adjuvantes siliconados na agricultura / Opportunities, regulatory and research demand and silicone adjuvant use on agricultureVeronese, Rogério 23 April 2015 (has links)
Atualmente, o mercado no Brasil de adjuvantes é de aproximadamente 400 milhões de dólares, sendo que a maior parte são os óleos, o que demonstra o pouco conhecimento sobre o uso de adjuvante organossiliconado. Foi realizada extensa revisão de literatura na Internet, Associações, Empresas privadas, bem como opinião de Especialistas. Pode-se concluir que os organossiliconados podem ser usados para herbicidas, fungicidas, inseticidas, reguladores vegetais, fertilizantes foliares e biopesticidas, devido às características toxicológicas e ambientais favoráveis, bem como os benefícios de melhoria da ação dos produtos, destacando-se a melhor performance em termos de penetração, absorção, retenção e cobertura de ingrediente ativo devido ao conceito de fluidez estomatal e penetração cuticular, que pode permitir redução do volume de água evitando a perda por escorrimento e permitindo melhor eficiência no manejo de problemas fitossanitários. Os adjuvantes organossiliconados não são iguais. Para se obter melhores resultados, é importante considerar: (i) as condições ambientais, (ii) as espécies vegetais, (iii) os sistemas de aplicação, (iv) o sistema de cultivo como um todo, (iv) os ingredientes ativos e (v) o alvo. A criação de uma regulamentação clara e simples é necessária, utilizando a normatização existente nos Estados Unidos como referência. Conforme discutido no Workshop sobre Adjuvantes Agrícolas no Brasil, promovido pelo Ministério da Agricultura, Pecuária e Abastecimento, o adjuvante deve ser tratado como um produto químico, o qual estará sendo combinado com os produtos agroquímicos existentes no mercado. Quanto às demandas de pesquisa, sugere-se estudar os diferentes adjuvantes organossiliconados com relação às suas propriedades, bem como as possibilidades de novas combinações personalizadas que forneçam o melhor desempenho quanto à melhoria da retenção e espalhamento para melhor cobertura das superfícies. Sugere-se ainda o levantamento de patentes existentes, bem como de material não compilado, incluindo produtos novos e do passado para criação de banco de dados. Um dos grandes usos dos siliconados tem sido com glifosato, visando reduzir perdas por lavagem e melhoria da eficácia. Para tanto, foi feito um ensaio sob condições controladas em casa de vegetação, na Universidade de São Paulo, com objetivo de avaliar o efeito da aplicação de surfactante organossiliconado juntamente com glifosato sob condições de chuva simulada. Utilizou-se a espécie Brachiaria decumbens, cultivada em vasos. Aplicações foram realizadas quando as plantas apresentavam um perfilho de cerca de 30 cm, 30 dias após a semeadura. Os experimentos conduzidos em delineamento inteiramente casualizado em esquema fatorial, sendo cinco doses de glifosato (0, 135, 270, 540 e 1080 g.ha-1 do i.a.) e três doses do organossiliconado Break Thru ® (0, 50 e 100 mL.ha-1), com três repetições cada tratamento. Foram conduzidos dois experimentos sem e com chuva simulada de 10 mm, 30 minutos após a aplicação dos tratamentos, sendo as avaliações (controle das plantas daninhas, índice Spad, peroxidação lipídica e massa seca) efetuadas aos 7 e 21 dias após a aplicação dos tratamentos. Observou-se o aumento do percentual de controle e redução no teor de clorofila na dose de 135 g.ha-1 de glifosato com 100 mL.ha-1 do surfactante com chuva simulada. / Nowadays, the Brazilian adjuvant market is approximately 400 million dollars. The most part are oils, that demonstrating low knowledge about organosilicone adjuvants. It was made an extensive literature revision in the Internet, Associations, Private companies, as well specialist opinion. Conclusions were that due to favorable toxicological and environmental characteristics, organosilicone adjuvant can be used with herbicides, fungicides, insecticides, growth regulators, foliar fertilizers and biopesticides. The benefits are improved efficacy of products. The improvement can result from enhanced penetration, uptake, retention or covering of active ingredients. Organosilicones are unique adjuvants in that they can produce stomatal flooding. There are different adjuvant organosilicone. To obtain better results is important taking in consideration: (i) environment conditions, (ii) vegetal species, (iii) application system, (iv) crop management, (iv) active ingredient and (v) target. The creation of simple and clear /regulatory rules for adjuvants in Brazil is needed, using the existent normatization in the USA as reference. According discussions in the Workshop about Adjuvants in the Agriculture in Brazil, promoted by Ministry of Agriculture, Livestock and Supply, the adjuvant must be treated as a chemical product, which will be combined with the existed agrochemicals products in the market. In relation of Research demands, suggesting study the different organosilicone products in relation the properties. As well the possibilities of new personalized combinations that supplying better performance in relation retention improvement and spreading to better surface covering. Suggesting to review all the existed intellectual properties, as well not compiled materials including new products and from past for creating of database. One of big uses of organosilicone had with glyphosate, for reducing wash off losses and efficacy improvement. However, it was carried a trial under controlled conditions in greenhouse, in the University of São Paulo, with objective of evaluate the application of organosilicone surfactant with glyphosate under conditions of simulated rain. The Brachiaria decumbens specie was cultivated in pots. Applications were made when the plants were one tiller of about 30 cm, 30 days after seeding. The experiments were carried out in randomized design, using a factorial scheme, five doses of glyphosate (0, 135, 270, 540 and 1080 g.ha-1 of a.i.), and three doses of silicone adjuvant Break Thru® (0, 50 and 100 mL.ha-1) with three replications for each treatment. Two experiments have been conducted without and with simulated rainfall of 10 mm, 30 minutes after application of the treatments. Seven and 21 days after treatment application the percentage of weed control, Spad index, lipid peroxidation and dry matter were evaluated. This effect was more dramatic in dose of 135 g.ha-1, as well as decreased Spad value, dry matter and lipid peroxidation increase, when associated with a dose of 100 mL.ha-1 surfactant.
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Oportunidades, demanda regulatória e de pesquisa e uso de adjuvantes siliconados na agricultura / Opportunities, regulatory and research demand and silicone adjuvant use on agricultureRogério Veronese 23 April 2015 (has links)
Atualmente, o mercado no Brasil de adjuvantes é de aproximadamente 400 milhões de dólares, sendo que a maior parte são os óleos, o que demonstra o pouco conhecimento sobre o uso de adjuvante organossiliconado. Foi realizada extensa revisão de literatura na Internet, Associações, Empresas privadas, bem como opinião de Especialistas. Pode-se concluir que os organossiliconados podem ser usados para herbicidas, fungicidas, inseticidas, reguladores vegetais, fertilizantes foliares e biopesticidas, devido às características toxicológicas e ambientais favoráveis, bem como os benefícios de melhoria da ação dos produtos, destacando-se a melhor performance em termos de penetração, absorção, retenção e cobertura de ingrediente ativo devido ao conceito de fluidez estomatal e penetração cuticular, que pode permitir redução do volume de água evitando a perda por escorrimento e permitindo melhor eficiência no manejo de problemas fitossanitários. Os adjuvantes organossiliconados não são iguais. Para se obter melhores resultados, é importante considerar: (i) as condições ambientais, (ii) as espécies vegetais, (iii) os sistemas de aplicação, (iv) o sistema de cultivo como um todo, (iv) os ingredientes ativos e (v) o alvo. A criação de uma regulamentação clara e simples é necessária, utilizando a normatização existente nos Estados Unidos como referência. Conforme discutido no Workshop sobre Adjuvantes Agrícolas no Brasil, promovido pelo Ministério da Agricultura, Pecuária e Abastecimento, o adjuvante deve ser tratado como um produto químico, o qual estará sendo combinado com os produtos agroquímicos existentes no mercado. Quanto às demandas de pesquisa, sugere-se estudar os diferentes adjuvantes organossiliconados com relação às suas propriedades, bem como as possibilidades de novas combinações personalizadas que forneçam o melhor desempenho quanto à melhoria da retenção e espalhamento para melhor cobertura das superfícies. Sugere-se ainda o levantamento de patentes existentes, bem como de material não compilado, incluindo produtos novos e do passado para criação de banco de dados. Um dos grandes usos dos siliconados tem sido com glifosato, visando reduzir perdas por lavagem e melhoria da eficácia. Para tanto, foi feito um ensaio sob condições controladas em casa de vegetação, na Universidade de São Paulo, com objetivo de avaliar o efeito da aplicação de surfactante organossiliconado juntamente com glifosato sob condições de chuva simulada. Utilizou-se a espécie Brachiaria decumbens, cultivada em vasos. Aplicações foram realizadas quando as plantas apresentavam um perfilho de cerca de 30 cm, 30 dias após a semeadura. Os experimentos conduzidos em delineamento inteiramente casualizado em esquema fatorial, sendo cinco doses de glifosato (0, 135, 270, 540 e 1080 g.ha-1 do i.a.) e três doses do organossiliconado Break Thru ® (0, 50 e 100 mL.ha-1), com três repetições cada tratamento. Foram conduzidos dois experimentos sem e com chuva simulada de 10 mm, 30 minutos após a aplicação dos tratamentos, sendo as avaliações (controle das plantas daninhas, índice Spad, peroxidação lipídica e massa seca) efetuadas aos 7 e 21 dias após a aplicação dos tratamentos. Observou-se o aumento do percentual de controle e redução no teor de clorofila na dose de 135 g.ha-1 de glifosato com 100 mL.ha-1 do surfactante com chuva simulada. / Nowadays, the Brazilian adjuvant market is approximately 400 million dollars. The most part are oils, that demonstrating low knowledge about organosilicone adjuvants. It was made an extensive literature revision in the Internet, Associations, Private companies, as well specialist opinion. Conclusions were that due to favorable toxicological and environmental characteristics, organosilicone adjuvant can be used with herbicides, fungicides, insecticides, growth regulators, foliar fertilizers and biopesticides. The benefits are improved efficacy of products. The improvement can result from enhanced penetration, uptake, retention or covering of active ingredients. Organosilicones are unique adjuvants in that they can produce stomatal flooding. There are different adjuvant organosilicone. To obtain better results is important taking in consideration: (i) environment conditions, (ii) vegetal species, (iii) application system, (iv) crop management, (iv) active ingredient and (v) target. The creation of simple and clear /regulatory rules for adjuvants in Brazil is needed, using the existent normatization in the USA as reference. According discussions in the Workshop about Adjuvants in the Agriculture in Brazil, promoted by Ministry of Agriculture, Livestock and Supply, the adjuvant must be treated as a chemical product, which will be combined with the existed agrochemicals products in the market. In relation of Research demands, suggesting study the different organosilicone products in relation the properties. As well the possibilities of new personalized combinations that supplying better performance in relation retention improvement and spreading to better surface covering. Suggesting to review all the existed intellectual properties, as well not compiled materials including new products and from past for creating of database. One of big uses of organosilicone had with glyphosate, for reducing wash off losses and efficacy improvement. However, it was carried a trial under controlled conditions in greenhouse, in the University of São Paulo, with objective of evaluate the application of organosilicone surfactant with glyphosate under conditions of simulated rain. The Brachiaria decumbens specie was cultivated in pots. Applications were made when the plants were one tiller of about 30 cm, 30 days after seeding. The experiments were carried out in randomized design, using a factorial scheme, five doses of glyphosate (0, 135, 270, 540 and 1080 g.ha-1 of a.i.), and three doses of silicone adjuvant Break Thru® (0, 50 and 100 mL.ha-1) with three replications for each treatment. Two experiments have been conducted without and with simulated rainfall of 10 mm, 30 minutes after application of the treatments. Seven and 21 days after treatment application the percentage of weed control, Spad index, lipid peroxidation and dry matter were evaluated. This effect was more dramatic in dose of 135 g.ha-1, as well as decreased Spad value, dry matter and lipid peroxidation increase, when associated with a dose of 100 mL.ha-1 surfactant.
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Influência da deposição de filmes finos organosilicones na fotodegradação do polipropileno / -Mena, Rodrigo Lemes 31 July 2013 (has links)
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Previous issue date: 2013-07-31 / Financiadora de Estudos e Projetos / It is known that polypropylene is degraded in the presence of UV radiation, making difficult its use in applications where occurs this kind of radiation. This situation arises a need to improve the properties of polypropylene under photodegradation. Some work was done in order to improve the surface properties of the polypropylene film with deposition of organosilicon, but the photoprotection caused by these films is still poorly studied. The purpose of this study was to deposit a film prepared from organosilicon plasmas of HMDSO (Hexamethyldisiloxane) on the surface of polypropylene films and verify the protection provided against photodegradation. Depending on the plasma deposition conditions, we detected a variation in the protection exerted by the deposited film. Among the tests, the chemical vapor deposition on low pressure plasma by radio frequency of 13.56 MHz using a mixture of gases with pressure O2/HMDSO added 6 Pa and a power of 80 W for a period of 1 h showed the best protection results, measured by comparing the evolution of the area in the region with the carbonyl peak at 1722 cm-1. FEG-SEM analysis showed that the film generated have adhesion to the substrate. Profilometry analyzes demonstrated that increasing the deposition time increases the film thickness and decreases its surface roughness. / É sabido que o polipropileno sofre degradação na presença de radiação UV, dificultando a sua utilização em aplicações onde ocorre incidência deste tipo de radiação. Surge assim a necessidade de se melhorar as propriedades do polipropileno em relação à fotodegradação. Alguns trabalhos foram desenvolvidos no sentido de melhorar as propriedades superficiais do polipropileno com a deposição de filmes de organosilicone, mas a fotoproteção originada por estes filmes ainda é pouco estudada. O propósito do presente trabalho foi o de depositar um filme organosilicone preparado a partir de plasmas de HMDSO (Hexametildisiloxano) sobre a superfície de filmes de polipropileno e verificar a proteção fornecida contra a fotodegradação. Dependendo das condições de deposição a plasma empregadas, detectou-se uma variação na proteção exercida pelo filme depositado. Dentre os testes realizados, a deposição de vapor químico por plasma de baixa pressão de radiofrequência de 13,56 MHz usando uma mistura de gases de O2/HMDSO com pressão de somada de 6 Pa e com uma potência de 80 W pelo período de 1 h foi a que apresentou melhores resultados de proteção, medida pela comparação da evolução da área da carbonila na região com pico em 1722 cm-1 As análises SEMFEG demonstraram que o filme formado tem adesão ao substrato. As análises de perfilometria demonstraram que o aumento do tempo de deposição aumenta a espessura do filme e diminui sua rugosidade.
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