The aims of this research work were to enhance the impact resistance and processibilty of wheat gluten (WG) by the addition of epoxidized natural rubber (ENR) compared to glycerol. This work was divided into two parts: to study the optimum ENR content for improvement of WG and the effect of together functions between ENR and glycerol on the properties of WG. Tested specimens were mixed and prepared by internal mixer and compression molding machine respectively. ENR and glycerol were varied from 10 to 40 phr. The effects of modifier types and contents on WG were evaluated by tensile impact and water absorption testing and thermal analysis. Fracture behavior and rubber dispersion were investigate with scanning electron microscope (SEM). The result revealed that the increase of ENR or Glycerol contents led to the decreases in tensile modulus and strength except for modifier content of 10 phr whereas elongation at break and impact strength increased. Glass transition temperature (Tg) of modified WG tended to decreased with the increase of ENR or glycerol contents especially for glycerol. The presence of glycerol affected on the decomposition temperature (Td) values but those were unchanged for case of ENR. Water resistant of WG specimen was improved by the presence of ENR whereas the increase of glycerol led to weight loss at immersion time of 2880 min. For the effect of ENR : glycerol ratios it indicated that glycerol enhanced tensile resistances but suppressed impact and water resistances of modified WG by ENR. Sizes and dispersion of ENR particles were improved by the addition of glycerol. Tg and Td values of modified WG by ENR and glycerol increased when ENR fractions were increased.

This research aims to develop the natural-rubber floor tiles mixed with high fineness ethylene vinyl acetate plastic wastes (EVA plastics) from the factories. The study use natural-rubber STR 20 at 100 phr with various contents of EVA plastics (e.g. 0 5 10 20 40 and 80 phr) and then mixed with chemical substance at constant ratio include zinc oxide at 5 phr stearic acid at 2 phr mercaptobenzothiazole at 0.5 phr diphenyl guanidine at 0.2 phr and sulfur at 3 phr. The samples are ground by two-roll mill and formed by compression molding at 150 degree Celsius with 30x30x0.2 cm of dimension. The properties of the natural-rubber floor tiles are tested under ASTM standard. From the results it is found that the natural-rubber floor tiles mixed with 10 phr of EVA plastics is the suitable ratio for using as the rubber floor tiles in building. This ratio can increase the hardness tensile strength and wear resistant properties and decrease the density and thermal insulation properties when compare to the natural-rubber floor tiles without EVA plastic.

This research aims to study the properties of natural rubber STR 20 at 100 phr with various contents of coir (e.g. 0 5 10 20 40 and 80 phr) and then mixed with chemical substance at constant ratio. After that the samples are ground by two-roll mill and formed by compression molding at 150 degree Celsius. This leads into the coir reinforcement natural rubber plate of dimension 30x30x0.5 cm. The properties of the natural rubber plates are tested under ASTM standard. From the results it is found that increasing in coir then the properties of resilience and density are improved at every mix ratio. However the tensile strength tear strength and wearing are increased at some certain value of coir. The samples give no water absorption at every mix ratio. The results from this research indicate that it can develop into the rubber floor tiles and rubber wall tiles for furnishing the buildings in natural style.

In this study natural rubber latex/chitosan (NRL/CT) composites were prepared by latex mixing. The effects of chitosan on latex properties and physical Properties of NRL/CT composite films were focused. It was found that there was no significant change in the latex properties with increasing CT content. Increasing CT contents of 0.5 to 8.0 phr caused the rising of 300 % modulus of the NRL/CT composite whereas the opposite trend was found for tensile strength and elongation at break. The antimicrobial efficacy of the chitosan-incorporated rubber was slightly enhanced from that of the non-chitosan rubber. By comprehensive consideration CT content suitable for antibacterial gloves according to Thai industrial standards (TIS 1056-1: 2013) was 1 phr. For other latex products that require high modulus and antibacterial activity such as tubing pillow foam rubber nipple and catheter CT could be used at higher contents from 2 to 4 phr.

The natural rubber with silica masterbatch was produced and used as based material in rubber compound modified from standard tread formulation given in ASTM E 1136. The reduction of mixing energy and rubber vulcanizate properties were investigated. Results indicate that in comparison with STR 5L compound the rubber with silica masterbatch i.e. fresh latex (FNRmSi) low viscosity natural rubber used 1.0 phr of hydrogen peroxide (LNR1mSi) and low viscosity natural rubber used 0.34 phr of hydrogen peroxide and 2.7 phr of potassium persulphate mixture (LNR2mSi) provides maximum mixing energy saving of 30.48% 33.37% and 37.20% respectively. The scorch time and cure time rise with increasing filler loading. The mechanical properties of LNR1mSi and LNR2mSi are similar to those STR5L compound whereas FNRmSi vulcanizate shows superior mechanical properties such as 300% modulus tear resistance abrasion resistance elongation at break and tensile strength. The homogenous distribution and interfacial interaction of silica filler and natural rubber matrix were enhanced by the self-assembled silica masterbatch as shown by the fracture surfaces morphology of the vulcanizate using a Scanning Electron Microscope (SEM). The silica masterbatch form has reduced the mixing power consumption and enhanced the mechanical properties.