Plasticizers are often interchanged with the idea that they will not affect the processing behavior of Polyvinyl Chloride (PVC). However, when the plasticizer type is changed, various complaints are made by the processors that the material no longer processes the same. This research was concerned with the effect of three different plasticizers on the plasticating extrusion behavior of PVC. Di-isodecyl pthalate (DIDP), di-hexyl pthalate (DHP) and 2-ethyl hexyl pthalate (DOP) are the three plasticizers used in this study. First some differences in the extrusion performance of the three differently plasticized PVC compounds were identified. In particular, it was observed that pressure build-up, flow rate and power requirement were affected by the plasticizer type with the DIDP plasticized materials generating higher pressures and requiring more power than the other two plasticized materials. The differences in extrusion characteristics have been observed for two different dies (1/8 and 1/16 inch diameter) attached to the extruder. The differences were most significant between the DIDP and the DHP plasticized mixes. Factors which could influence the processing behavior of plasticized PVC include viscosity, compaction, thermal conductivity, specific heat, and friction coefficient. It was found that all other properties other than the viscosity were unaffected by the plasticizer type. On the other hand, viscosities were significantly affected by the plasticizer type with the DIDP plasticized materials displaying higher values between 160 and 190 °C. The difference in viscosity was larger between the DIDP and DHP plasticized materials than between DIDP and DOP plasticized materials. The differences in viscosity between DIDP and DOP plasticized materials tend to diminish considerably at 190 °C. Two flow regions characterized by different degrees of fusion above and below 165 °C were identified for the plasticized PVC compounds. Plasticized PVC exhibited yield stresses with the DIDP plasticized materials having higher values. The yield stresses were responsible for the significant difference in viscosity at lower shear rates. The yield stress was a more dominant feature at temperatures below 160 °C and this fact was made use of in modeling the solids conveying zone as a fluid with yield stress. Correlation was established between the viscosities and the extrusion behavior of the plasticized PVC compounds. It was observed that the DIDP plasticized mixes had higher viscosities, fused earlier in the screw channel, gave rise to higher pressures, required more power and in general exhibited higher flow rates at the same screw speed. The finite element method was used for the numerical simulations. Based on the experimental results, the numerical modeling of the melt zone was performed in order to predict the differences in the extrusion characteristics. The melt zones were modeled as a temperature dependent power law fluid having two different viscosity expressions above and below 165 °C. The numerical predictions for pressures and flow rates in the extruder with the 1/8 inch diameter die were in good agreement with the experimental results. For the case of the 1/16 inch diameter die attached to the extruder, the numerical and experimental flow rates were in good agreement but the pressure predictions, although indicating the correct trends, were off by 15 to 20% from the experimental results. In general the differences in the physical properties, viz. viscosities, were used to predict the differences in the pressure build-ups and flow rates. Also the solid conveying zone was modeled using a Herschel Bulkley model. It was possible to match the experimental and numerical results for the solids conveying zone by using an average density value for the entire solids conveying zone, but more work needs to be done in order to establish greater validity and applicability of this model. / Ph. D.

The study presented here consists in an original piece of work to better understand complex food packaging interactions. The majority of investigations on food polymer interactions related to orange juice and this provided a good base to our study (Literature reviews: cf. Chapters 1a and b). Additionally a rather remarkable finding in 1994 was that limonin, a trace bitter material found in some varieties of orange juice was rapidly absorbed by highly plasticised polyvinyl chloride (PVC plastisol) (Chapter 2). Several commercial absorbants are available for debittering, relying on limonin absorption on the large surface area of the highly porous absorbant pellets. However, the absorptive properties of the smooth plastisols apparently relied on a different mechanism. Limonin is a very large (470.5 g/mol) compound, but some preliminary experiments with another much smaller orange juice constituent d- of absorbates in plastisols, methods used earlier (Moisan 1980, Holland and Santangelo 1988) to measure solubilities and diffusion constants in packaging films could be advantageously used to survey these properties in a wide range of materials, including model compounds of various types, and a number of compounds which may be found in citrus juices (Chapters 3, 4 and 5). Experimentally, the method found most suitable was to use a ‘test film’ of pure plastisol which was wrapped tightly on both sides by a similar ‘supply film’ blended with 1 Molar test material (also called ‘absorbate’), setting up a concentration gradient. The inner test film was removed at regular intervals (minutes to hours) to measure (mainly by weighing) the uptake of the test reagent with time. Rather unexpectedly, it was found in a number of cases that the test film lost weight, either from the beginning, or after a period of time. Three main types of behaviour were identified: Type A lost weight from the beginning and over a long period of time, Type B gained weight initially and then lost weight, and Type C gained weight until a steady state was reached. Often the maximum, or near maximum, mass increase occurred within around 100 minutes, indicating a very rapid, liquid-like diffusion mechanism, in harmony with the rapid uptake of d-limonene and limonin. The major parameters of interest with these compounds are their diffusion rates and their solubilities, and in the presence of aqueous media (orange juice and other foodstuffs) the partition coefficient between the plastisol and water, which is related to the hydrophobicity function LogP for the compound. The major complicating factor in these measurements is the observation that the plasticiser materials themselves also migrate, in the reverse direction, because of the lower effective concentration in the supply film. This effect tends to be small, but is one explanation for the mass loss observed above, and cannot be ignored over the long term, nor in its practical applications to contamination in foods. There are many possible applications for the techniques described above. The removal or addition of compounds in food packaging itself is one. Upgrading foods, such as orange juice, commercially, is another. In many cases ‘scalping’ off-flavours or other minor components takes place exclusively through solid or liquid contact with the packaging. The removal from the headspace measured by the current gas permeation methods is irrelevant for the vast numbers of involatile, but easily diffusable compounds. For such compounds these novel applications are simple and rapid, require little specialised equipment, and fill a niche in the armoury of food and packaging chemists. / Doctor of Philosophy (PhD)

The applications of membrane technologies have dramatically increased during the last few decades due to technology improvement and cost reduction. Membrane applications can be found in water and wastewater treatment, pharmaceutical industry, chemical processing industry, food industry, etc. However, the membrane technology faces two major challenges: membrane fouling and membrane lifetime. During the membrane filtration process, membrane fouling caused by natural organic matter (NOM) is an inevitable phenomenon, and physical cleaning or chemical cleaning are required for recovering the performance of membrane. As a result of these cleaning processes, membrane lifetime is shortened. For this reason, it is necessary to improve membrane's fouling resistance and lifetime in order to apply membrane technology in large-scale facilities. This dissertation focuses on improving the fouling resistance and flux performance of polyvinyl chloride (PVC) membrane and polyvinylidene fluoride (PVDF) membrane. Specifically, it is comprised of four parts. First, I prepared PVC membranes by adding different amounts of amphiphilic copolymer (Pluronic F 127) into PVC casting solutions. I optimized the performance of PVC membranes by changing the amount of Pluronic F127 used in the casting solution. The results show that with the increase of Pluronic F 127 content, the pore size and pore density both decrease. Moreover, the membrane surface becomes more hydrophilic as indicated by lower contact angles. In addition, the PVC membrane exhibits remarkable antifouling characteristics after adding Pluronic F 127. Second, I synthesized PVDF membranes by adding PVDF graft poly(ethylene glycol) methyl ether methacrylate (PEGMA) (PVDF-g-PEGMA) as additive in casting solutions via the phase inversion method. The synthesized PVDF membranes have unique pillar-like structures on surfaces, which gives the PVDF membrane a defect-free feature and allows it to generate high flux under low pressure. Third, I investigated the forming mechanism of the pillar-like structure from aspects of solvent and additive. Finally, I investigated the influence of PEGMA dose on the performance of PVDF membranes. I changed the amount of PEGMA used in the casting solution and compared the performance of the synthesized PVDF membranes. To summarize, this dissertation has deepened our understanding of how to improve the fouling resistance and flux performance of PVC membranes and PVDF membranes by using amphiphilic copolymer. In addition, the PVDF membrane I synthesized has unique pillar-like structures that give it defect-free and high flux properties. Overall, the results of this study provide valuable information for PVC and PVDF membrane synthesis for large-scale production.

Thesis (Ph.D.) -- University of Western Sydney, 2004. / A thesis presented to the University of Western Sydney, Centre for Advanced Food Research, in fulfilment of the requirements for the degree of Doctor of Philosophy in Advanced Food Science (& Food Packaging Science). Includes bibliography.

Zugl.: Köln, Universiẗat, Diss., 2008.

Thesis (Ph.D.)--Technical University of Denmark, 2001. / Title from PDF title page (viewed on Feb. 20, 2009). "September 2001". Includes bibliographical references (p. 99-104).

M.Sc. (Chemistry) / The fabrication of multiwalled carbon nanotube/polyvinyl chloride (PVC) composites and a study of their thermal, fire retardancy and mechanical properties are reported. Triphenylphosphine linked - multiwalled carbon nanotube (TPP-MWCNT) and pristine MWCNT were used. The MWCNT were embedded in the polymer matrix through melt blending and solvent casting. The phosphorylation of the MWCNT and their dispersion in the PVC matrix was characterized by scanning electron microscopy and Raman spectroscopy. Thermal analysis of the nanocomposites by thermal gravimetric analysis (TGA) in both solvent casting and melt bending processes, showed different results when compared with the neat PVC. The modulus of the MWCNTs / PVC nanocomposites synthesized via melt blending increased, whilst there was a reduction in their tensile strength, indicating a decrease in polymer toughness. The tensile modulus and strength of MWCNTs / PVC nanocomposite synthesized via Solvent casting decreased whilst there was an increase in Tpp-MWCNT/PVC nanocomposite when compared with its counterpart MWCNTs / PVC nanocomposite, indicating an increase in stiffness and strength. The limited oxygen index (LOI) fire retardant tests of all the neat PVC and its nanocomposites showed no value difference.

The bonding of plastic sheeting to metal is a recent development of the surface coating industry. The product, a pre-finished material, has the strength of the base metal and exterior finish of the plastic. It is used in making radio and television cabinets, furniture, and chemical containers. In order to improve the bonding practice, it is necessary for the engineer to be well informed of the fundamental principles involved. A knowledge of the theory of bonding, the nature of the bond, and the factors affecting the bond strength would be helpful in attaining this goal. The purpose of this investigation was to study the factors affecting the bond strength between polyvinyl chloride sheeting and metal. The metals used in this investigation were aluminum, brass, copper, nickel, low carbon steel, and stainless steel. The plastic sheeting was bonded to the metal by means of synthetic adhesive. Five different commercial adhesives were used. These were vinyl chloride-acetate resin, VYNW, modified vinyl chloride-acetate resin, VMCH, vinyl acetate resin, A-70, vinyl alcohol-acetate resin, T-24-9, and vinyl alcohol-acetate resin, MA-28-18. The specimens of metal were treated as follows. Three sets of specimens were prepared. The first set was degreased with solvent only, the second one was polished and degreased, and the third one was degreased and etched. Semi-rigid polyvinyl chloride sheeting was bonded to the metal at a temperature of 70°, 150°, 250°, and 350°F under a pressure of 200 pounds per square inch. A series of the bonded specimens was stretched to 10, 20, and 30 percent elongation. A series of steel-steel laminates was prepared. They were bonded by different adhesives at 250°F under 200 pounds per square inch. The specimens of this series were tested for shear strength. The effect of surface conditions, of bonding temperatures, of nature of metals, of types of adhesives, and of amount of plasticizer in the adhesive upon the bond strength between polyvinyl chloride sheet and metal was determined and the following conclusions were reached: 1. The bond strength was affected by surface conditions. Etched specimens had higher bond strength than polished ones except low carbon steel. 2. The bonding temperature had no definite influence on the bond strengths of aluminum, nickel, low carbon steel, and stainless steel laminates. 3. The bond strengths of brass and copper laminates increased with the bonding temperature. 4. The average bond strengths of polished specimens of low carbon steel, aluminum, stainless steel, nickel, copper, and brass were 19.6, 15.5, 14.2, 8.5, 5.5, and 2.5 pounds per inch respectively. The strengths of these metal laminates followed the order of these metals in the galvanic series except aluminum. 5. The adhesion between adhesive and metal varied directly with the polarity of the adhesive. 6. The bond strength was also affected by the amount of plasticizer in the adhesive. When the laminates were subjected to stretching, the rate of decrease in strength was inversely proportional to the amount of plasticizer in the adhesive. / Master of Science

Pyrolysis-capillary gas chromatography combined with FID, ECD and MS detection were used to characterize refuse-derived fuel and aquatic fulvic acids. Different pyrolysis methods and programs were evaluated. Pyrolysis temperatures of 700-800°C produced the strongest signal for organics present in RDF and fulvic acid. Cellulose and fatty acids pyrolyzates were identifiable by GC-MS following preparative pyrolysis fractionation. At organic chloride content of 0.023%, only three halogenated compounds were detected in the GC-MS of the fractions. None of the priority pollutants were detected at lower detection limit of 0.72 to 24 mg/ kg RDF. Selective solvent extraction improves the reproduciblities of the technique and allows the detection of polymeric structures. Pyrograms of polyvinyl chloride and regular typing paper showed some common peaks that are present in the RDF pyrogram. About 65% of the peaks in the RDF pyrogram might be of paper origin. The organic chloride content of the RDF was evaluated by ion chromatography of the trapped pyrolyzates in 2% NaOH trap and it was found to be 221 mg Cl/ kg dry RDF. Pyrolysis conditions and temperature programs for FA were systematically evaluated. Samples included purified FA, methylated FA and HPLC separated fractions. Characteristic pyrograms were developed. Profiles of benzene, toluene, phenol, m-cresol and biphenyl from FA were evaluated. The production of phenol was the largest at 800°C, at concentration of 1.61 mg per gram of FA pyrolyzed. The profiles of benzene and toluene followed the same pathways. Both pyrolyzates had at least two precursors. HPLC fractions of FA showed some regular retention patterns characteristic of polymeric material. DL-proline, seriene and vanillic acid pyrograms showed some peaks with the same retention times as those in FA pyrogram under the same conditions. A reproducibility of 6% relative standard deviation was achieved in the pyrolysis of RDF and 0.91% in the case of FA.

Orientador: Marcos David Ferreira / Resumo: Objetivo. Analisar a eficácia antimicrobiana in vitro de compósito em pó a base de prata e sua aplicação em diferentes concentrações em filmes de policloreto de vinila (PVC) produzidos em escala industrial e em laboratório. Métodos. Um material compósito constituído por dióxido de sílicio (SiO2) e nanopartículas de prata (NpAg), produzido e cedido por uma empresa de soluções tecnológicas, foi caracterizado por Microscopia Eletrônica de Varredura (MEV), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Filmes de PVC industrial aditivados com 6,25, 12,5, 25 e 100 ppm de NpAg e filmes produzidos laboratorialmente pelo método de casting aditivados com 12,5, 25 e 100 ppm de NpAg foram caracterizados por Microscopia Eletrônica de Varredura (MEV), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Testes microbiológicos in vitro foram realizados com o compósito de prata e com os filmes de PVC. Com o compósito realizou-se o Teste de Difusão em Ágar por poço e a Contagem de Microrganismos Viáveis. Com os filmes industrial e laboratorial realizou-se o teste da Norma JIS Z 2801:2000, e com os filmes industriais realizou-se os testes de Agitação em Frasco e Contagem de Microrganismos Viáveis. Resultados. O compósito apresentou inibição para Escherichia coli em todas as concentrações estudadas e para Staphylococcus aureus nas concentrações de 12,5, 25 e 100 ppm de NpAg. A adição de compósito na matriz... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre