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Poly(dimethylsiloxane) (PDMS) was modified with poly (2-hydroxyethyl methacrylate) (PHEMA) by a blending method in order to enhance the hydrophilicity and biocompatibility. Collagen (type I) was also linked onto the modified films via methyl sulfonyl chloride. Collagen finally reacted with the activated groups to obtain covalently linked protein layers. The surface morphologies of polymer blends were characterised using ATR-FTIR, XPS and SEM. DMTA analysis and tensile testing were used to investigate the physical and mechanical properties of the blends. Water uptake and water contact angle measurements were performed on the polymer blends in order to evaluate their surface wettability. The biocompatibility of samples was evaluated by culturing fibroblast cells (L929). Grafting of collagen onto the surface was confirmed using ATR-FTIR and XPS. The mechanical properties of modified PDMS did not change greatly in comparison to pure samples. Collagen linked surfaces showed significant cell adhesion and growth.

This study focused on the effect of chemical modification of oil palm empty fruit bunch (EFB) filler on the flexural and impact properties of EFB-filled polypropylene (PP) composites. EFB filler has been chemically modified with maleic anhydride (MAH). The modification involved the reaction of EFB and MAH (dissolved in dimethylformamide) at 90°C. The composites with MAH-treated EFB showed higher flexural and impact strength than those with untreated EFB. The modification had significantly improved the flexural modulus and toughness of the composites. This may be attributed to the enhanced adhesion between the MAH-treated EFB and PP matrix, as shown in the scanning electron microscopy (SEM) study. Fourier Transform Infra-Red analysis (FTIR) showed evidence of C=C and C=O groups from MAH at 1630cm−1 and 1730cm−1, respectively. The analysis also showed a reduction of absorption at 1630cm−1 for MAH modified EFB–PP composites which indicated the reaction of C=C from MAH with PP.

The effects of cetyltrimethylammonium maleate (CTMAM) on curing characteristics and mechanical properties of carbon black-filled polychloroprene rubber (CR) were compared with a conventional curative system viz. combinations of ethylene thiourea (ETU), zinc oxide, and magnesium oxide. Results show that the scorch time and cure time decrease as the concentration of CTMAM is increased. However, both properties are comparable to the conventional curative system (control compound) at a concentration of 3 phr. It was also found that CTMAM was capable of functioning as a cross-linking agent for polychloroprene rubber (CR). CR compounds with 3 phr of CTMAM also show comparable tensile strength and hardness to the control compound whereas resilience decreases with increasing CTMAM concentration.

The degradation and moisture uptake of sago-starch-filled linear low-density polyethylene (LLDPE) composites have been studied. Enzymatic hydrolysis of the composites apparently involves surface starch granules; embedded granules are not easily accessible because of the poor moisture absorption or transmission property of the matrix. Exposure of the composites to weathering resulted in massive deterioration typified by turbidity, discoloration, embrittleness and dimensional changes. Soil burial led to a drop in the pH of the soil and the presence of holes on the samples, probably due to microbial activity. Furthermore, the drop in mechanical properties of the composites increased with time of burial for the first four months and decreased gradually thereafter. Moisture uptake increased with increased starch content and immersion time. The time taken for the composites to equilibrate was about three months even when they were immersed completely in water. The mechanical properties of the composite also dropped with increasing moisture uptake.

Mechanical properties of composites made from sago starch (SS) and LLDPE have been investigated. Mechanical properties such as tensile strength (TS) and elongation at break (EB) decreased with increasing starch content while the modulus increased. Composite equations of Kerner, Nielsen and Halpin-Tsai were used to explain the effect of filler volume fraction on the mechanical properties of the composites. Disagreement occurs between experimental and theoretical data as filler volume fraction of the composites increases.

The effects of using cetyltrimethylammonium maleate (CTMAM) and N-cyclohexyl-2-benzothiazole-2-sulphenamide (CBS) as an accelerator in carbon black filled natural rubber compounds were studied. Results show that curing time, t 90 and scorch time, t 2 are faster for CTMAM compared to CBS. CTMAM can function in its own right as an accelerator for sulphur vulcanization without the presence of zinc oxide and stearic acid as activators. The use of CTMAM without the presence of zinc oxide and stearic acid not only gave good tensile and tear strengths, tensile modulus, rebound resilience and hardness but was better compared to the use of commercial CBS.

The melt rheological behavior of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) thermoplastic elastomers (TPEs) was studied with a special reference to the effect of dynamic vulcanization, apparent shear rate and temperature using a twin screw capillary rheometer. PVC/ENR TPEs were compounded with a HAAKE twin screw extruder (WCT100). At a particular temperature it was found that the apparent viscosity decreased with increased in apparent shear rate following a pseudoplastic behavior, thus indicating that the dynamically vulcanized TPEs are processible as thermoplastics. The elastic phenomena was investigated by calculating the die swell which was found to be affected by the apparent shear rate and processing temperature. The extrudate surfaces at different apparent shear rates were studied by means of optical microscopy. It was observed that as apparent shear rate increases the extrudate surface exhibits a higher degree of deformation, the extent of which is also dependent on the sulfur concentration.

A simple and accurate method for determination of filler material density is described. Rice husk ash (RHA) which consists predominantly of silica serves as a filler in polypropylene. The filler density was determined from first principles using a pyknometer. The filler was compounded in polypropylene and the densities of the composites were measured using an electronic densimeter. The measured composite densities agree very closely with theoretical values calculated based on the measured density of the filler material.