Det här projektet har utförts på Scania och är en förstudie till en standardbeskrivning där olika bindemedel i ledningsnät studerats för att kunna användas i olika miljöer i lastbilen så som hytt chassi och drivlina. Olika krav som temperatur, kemikaliebeständighet och fuktresistans ställs för de olika miljöerna. Bindemedlet ska hålla kablarna på plast i en skyddsslang och samtidigt fungera som tätning. De limtyper som har studerats i den här rapporten är ett epoxilim, ett epoxy-cyanoacrylate hybrid lim, ett smältlim av polyamid och två siliconlim. De har limmats på några av de platser som används i lastbilen och sedan utsatts för dragtester, kemikalietester, åldring- och klimattest. Inget av de testade limmerna klarade alla testerna men den limgrupp som klarade testen bäst var de av silicon. / This project has been performed at Scania and it is a pre-study for a standard description of binders in cables harness in different environments in the truck. The different environmental zones are the cab, chassis and power train. Different zones in the truck have different requirements such as temperature, chemicals and moister resistance. The function of the binder is to glue cables into a protective hose of plastic and also act as a seal. The different types of adhesives that have been study in this report is epoxy adhesive, epoxy-hybrid cyanoacrylate adhesive, hot melt by polyamide and two types of silicon glue. They have been glued to some of the different plastics that the cables are made of in the truck and then they have been exposed to tensile tests, chemical tests, aging and climate tests. None of the tested adhesives passed all the tests, but silicon glue passed most of the tests.

Different native starches, modified starches and plant proteins were evaluated as wood adhesives. They were combined with different synthetic polymers in order to achieve improved adhesive properties. The study was divided into two parts: development of starch based adhesive formulations and evaluation of an existing protein based adhesive.  Eight different starches and two different plant proteins were used in the first part. Starch 1 and starch 2 as well as protein 1 and protein 2 were some of the used materials. These materials were dispersed in synthetic polymers such as poly (vinyl acetate) (PVAc), styrene-butadiene rubber (SBR), poly (vinyl alcohol) (PVA), poly (acrylic acid) (PAA) and poly (ethylene-co-vinyl acetate) (EVA). Five different cross-linking agents were also tested. In the second part of the study, protein 2 was used as a renewable material. It was dispersed in dispersing media 2 and filler 1 was used. In an effort to increase the amount of renewable material in the adhesive composition, six different renewable fillers were examined. Lower pressing temperatures as well as lower amounts of cross-linking agent 1 were evaluated in order to observe their influence on the adhesive properties of the protein based adhesive. All formulations were characterized by measurement of viscosity, solid content and pH. The adhesive properties of some of the formulations in both parts of the study were characterized according to SS-EN 204:2001 and EN 14257 (WATT 91). The best results, of the starch based formulations, were obtained when starch 1 and protein 2 were dispersed in dispersing media 2 or dispersing media 7. These formulations in combination with cross-linking agents were classified as D2 and passed the criteria for heat resistance (WATT 91). However, the results were comparable with the reference sample. It was possible to replace filler 1, totally or partly, in the protein based adhesive with renewable fillers. Protein based adhesive formulations with filler 2 and filler 4, amongst others, showed improvement of the adhesive properties. These formulations passed D3 and D4 – wet criteria and almost passed D4 – boiling criteria. The amount of renewable material in the protein based adhesive was increased from ~32 % to ~56 % in the formulations that obtained the best adhesive properties. The amount of non-petrochemical material was ~67 % in all new formulations as well as in the reference sample.  By decreasing the pressing temperature from 110 °C to 90 °C or by decreasing the amount of cross-linking agent 1 from 15 % to 5 %, a protein based system that passes D3 criteria can be obtained.

Oxidative degradation of adhesives based on silane terminated polypropylene oxide and polypropylene oxide (PPO) was studied. The combination of rapeseed oil and PPO as plasticizer in the parquet adhesive gave rise to oxidative degradation in contact with screeds of certain minerals. In order to investigate the degradation process in parquet adhesive two experimental approaches were employed in parallel. The first method was ageing of a solid adhesive-screed system at elevated temperature. It was done in order to evaluate the effect of contact between adhesives and screed in different adhesive-screed systems. Another purpose was also to identify the degradation procedure in a system resembling reality. The second method used was ageing of a soluble mixture of pure PPO with selected plant oils; in order to study the affect of oils unsaturations on the PPO by FTIR. FTIR was used to monitor the degradation of samples after different exposure periods. Unfortunately, interference from the adhesive additives made monitoring of the degradation process difficult in this approach. On the other hand, the optical inspection of the samples degradation process gave a clearer overview. A second method, looking only at two components mixed e.g. PPO and Oil, gave clear FTIR spectra showing that the oxidation process of rapeseed oil started in the period before fifteen days ageing at 75 oC. The combination of FTIR and optical inspection gave a clear image of the adhesive degradation process. Interaction between unsaturated carboxylic acid in the vegetable oils and PPO can increase the degradation rate of parquet adhesives by a radical mechanism. Another parameter affecting the degradation is the interfacial interaction between adhesive containing PPO-Rapeseed oil as plasticizer and screed with high alkalinity, porosity and humidity. The alkaline and humid conditions in the screed probably increase the hydrolysis of rapeseed oil. Further, the porosity of the screed provides a large surface area enabling the plasticizer to be exposed to plenty of oxygen from the air. Therefore, the plasticizer is not only exposed to hydrolysis but also oxidation. This would support the observation of migration of the rapeseed oil, since it is known that carboxylic acid has affinity to calcium sulfate anhydrite in the screed material. Migration and oxidation of rapeseed oils carboxylic acid generate radicals, which accelerate the degradation of PPO in the adhesive film. This process correlated with disappearance of PPO absorbance band from the spectrum.

Cellulose nanocrystals (CNCs) are attractive nanomaterials due to their superior mechanical properties, renewability, and natural abundance. Their surface hydroxyl groups, along with surface charges induced during their production, allow CNCs to be easily dispersed in an aqueous medium, especially with sustainable water-based production methods such as emulsion polymerization. Moreover, their surface functionality makes them highly suitable for modification, thereby making them even more versatile. Emulsion polymer latexes are heterogeneous mixtures, having a continuous aqueous phase along with a dispersed organic phase. Latex polymers are used in a wide range of applications such as in coating and adhesive films. Because of the bi-phasic nature of emulsion polymerizations, the surface properties of CNCs play a crucial role in their location relative to the organic phase, and how well-dispersed they are in the cast films. In this thesis, three grades of CNCs (Celluforce Inc.) with either hydrophilic, partially-hydrophobic, or hydrophobic surface properties, were combined with conventional emulsion and miniemulsion polymer formulations to investigate their effect on the properties of pressure sensitive adhesive (PSA) films. In the first instance, hydrophilic CNCs were tested in a seeded semi-batch emulsion polymerization. Using a sequential experimental design, the effects of polar comonomer, surfactant, chain transfer agent, and CNC loading on latex stability and PSA properties were studied. By increasing polymer chain entanglements and the work of adhesion, the hydrophilic CNCs were observed to simultaneously improve the three key properties of acrylic-based PSA films, i.e., tack, peel strength and shear strength. In the second part of this project, we compared the role of hydrophilic and partially-hydrophobic CNCs in PSA property modification. Viscosity measurements and atomic force microscopy revealed differences in the degree of association between the two types of CNCs and the latex particles. Dynamic strain-sweep tests showed that hydrophilic CNC nanocomposites softened at lower strains than their partially-hydrophobic counterparts. This behaviour was confirmed via dynamic frequency tests and modelling of the nanocomposites’ storage moduli, which suggested the formation of CNC aggregates of, on average, 3.8 and 1.3 times the length of CNCs. These results confirmed that the partially-hydrophobic CNCs led to improved CNC dispersion in the PSA films and ultimately, enhanced PSA properties. In the third part of the project, mini-emulsion polymerization (MEP) was used to embed the hydrophobic CNCs within the polymer particles in contrast to the hydrophilic and partially-hydrophobic CNCs which resided mainly in the aqueous phase or near the water-particle interface. Higher CNC loadings led to increased particle size, decreased polymerization rate and number of particles, while only slightly increased the viscosity and the work of adhesion. PSA film properties decreased upon the incorporation of hydrophobic CNCs. Transmission electron microscopy showed that CNCs were expelled from the latex particles at higher loadings, suggesting the incompatibility of the acrylic polymer and the CNCs’ modifying agents. The ability to modify CNCs enables one to achieve a range of hydrophilicity/hydrophobicity. This makes them extremely versatile in a heterogeneous mixture such as in an emulsion polymerization. Because emulsion polymers are used in a wide range of applications with a broad spectrum of properties (i.e., not only as adhesives but as non-tacky coatings), our ability to control CNC location relative to the polymer particles in the latex opens the door to a world of high value-added sustainable polymer products.

Joining of uniformly-curved composite sandwich panel segments, typical in state of the art aerospace launch vehicles, should be mass-efficient. Adhesively bonded joints can provide increased mass-efficiency over mechanically-fastened joints. But, due to manufacturing sensitivities and certification requirements, conventional bonded joints can be improved upon by introducing structural redundancy. A longitudinal, durable redundant joint (DRJ) architecture featuring multiple adhesive load-paths, via a novel composite preform insert, was proposed to join composite sandwich panel segments of the interstage element for NASA's Ares V launch vehicle. A series of twenty-five static linear-elastic finite element models with plane strain solutions were developed to assess certain characteristics of a joint's structural response when subjected to a simplified circumferential hoop loading convention. Shear and normal stress distributions at the adherend-adhesive interface along the splice plate bondline of the DRJ are compared with those from a conventional splice joint (CSJ) configuration for a series of linearly increasing bondlines thicknesses and joint overlap lengths. The parameter studies indicate the DRJ configuration's adhesive peak stresses are independent of the joint overlap length at the joint edges. Also, simulated bonding defects, in the form of local adhesive gaps, due to manufacturing processes are investigated to determine the load path redistribution for the DRJ and CSJ configurations. Results for pristine versions of both configurations are included. The defective CSJ joint exhibits severe overloading of certain laminates, while the defective DRJ load redistributions are relatively mild. Between the two primary types of bondline gaps considered for the DRJ configuration, the gap corresponding to the splice plate, a more mature manufacturing operation and also a more easily inspected location than the insert-to-face sheet interface, is noted to be more severe. A direct joint-to-joint mass-comparison reveals a 164% increase in mass, per unit thickness, between the CSJ and DRJ. To put this in perspective, a second comparison is made using a four-segment sandwich panel barrel. A 3.51% increase in mass is observed between the CSJ and DRJ-based cylinders. Also, for a simplified sizing philosophy, based solely on the peak stresses in the adhesive domain, a CSJ may require a 1.5-inch longer joint overlap than a DRJ. The mass-estimate is recomputed, and the mass percent-increase of the segmented cylinder is reduced to 2.61% over a CSJ configuration. / Master of Science

Indiana University-Purdue University Indianapolis (IUPUI) / The “total-etch” or “etch-and-rinse” systems have been the gold standard of dental bonding for decades. However, these systems are very technique-sensitive and time-consuming compared to newer “self-etch” or “self-adhesive” systems and have been implicated in cases of postoperative sensitivity. The purpose of this study was to compare the effects of two surface treatment protocols (self-etch vs. selective-etch) on the clinical performance of a universal adhesive and resin composite in Class V non-carious cervical lesions (NCCLs). Thirty-three volunteer subjects (17 male; 16 female; age range = 20 to 75 years) having at least two NCCLs were selected from patients of record at Indiana University School of Dentistry. Each subject received one resin composite restoration (Tetric EvoCeram, Ivoclar Vivadent) utilizing a self-etch (SfE) universal adhesive (Adhese Universal, Ivoclar Vivadent) with no separate enamel etching and another restoration utilizing adhesive and selective enamel etching (SelE) with 37% phosphoric acid (H3PO4). Both the adhesive and composite were placed following the manufacturer’s instructions. The two techniques were compared for differences in sensitivity, retention, marginal discoloration, marginal adaptation, and clinical acceptability at baseline and 6 months using the Cochran-Mantel-Haenszel tests for stratified, ordered categorical outcomes. Seventy-four restorations (37 SfE, 37 SelE) in 30 volunteers were evaluated at 12 months. No significant differences were found between the SfE and SelE groups for any variable at the 12-month recall (p>0.21). Retention was 100% at 12 months for both groups. Marginal adaptation was significantly worse at 12 months than at baseline for SelE (p=0.0163), but there was no difference for SfE (p=0.08). Sensitivity improved significantly from baseline to 12 months for both SelE (p=0.0113) and SfE (p=0.0128). The results obtained from this study are comparable to results observed in similar studies. Like similar studies involving self-etch adhesives in non-carious cervical lesions, our study showed no restorations lost to caries and excellent retention. The deterioration of selective-etch dentin margins was a result that differed from similar studies. A likely explanation for this finding would be the difficulty of controlling precise placement of phosphoric acid gel, causing undesired etching of dentin; this could result in suboptimal bonding to dentin. This report on 12-month data for a two-year study indicates significantly reduced sensitivity for both the SelE and SfE groups, and deterioration of SelE marginal adaptation. No decreases in retention, marginal discoloration, or clinical acceptability were observed in either group.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19774号 / 農博第2170号 / 新制||農||1040(附属図書館) / 学位論文||H28||N4990(農学部図書室) / 32810 / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 植田 充美, 教授 栗原 達夫, 教授 矢﨑 一史 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19776号 / 農博第2172号 / 新制||農||1041(附属図書館) / 学位論文||H28||N4992(農学部図書室) / 32812 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 金山 公三, 教授 矢野 浩之, 教授 五十田 博 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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Bonding composite structures using adhesives offers several advantages over mechanical fastening such as better flow stress, weight saving, improved fatigue resistance and the ability to join dissimilar structures. The hesitation to adopt adhesively bonded composite joints stems from the lack of knowledge regarding damage initiation and propagation mechanisms within the joint. A means of overcoming this hesitation is to continuously monitor damage in the joint. This study proposes a methodology to conduct structural health monitoring (SHM) of an adhesively bonded composite lap joint using acoustic, guided Lamb waves by detecting, locating and predicting the size of damage. Finite element modeling of a joint in both 2D and 3D is used to test the feasibility of the proposed damage triangulation technique. Experimental validation of the methodology is conducted by detecting the presence, location and size of inflicted damage with the use of tuned guided Lamb waves.