The objectives of this research were to study the personal and environment and investment experiences factors influencing decision making to invest in the provident funds of The Office of the Rubber Replanting Aid Fund’s Staffs. The sample consisted of 341 persons from Rubber Replanting Aid Fund’s staffs at Bangkok office (central region). The research instrument was a questionnaire and using the descriptive statistic such as mean percentage standard deviation to analyze the data and Exploratory Factor Analysis : EFA and Binary Logistic Regression Analysis to test the hypothesis. The results of the study found that sex age the knowledge and investment experiences the risks of investment the economy the politics differences influencing the decision making to invest in the provident funds of The Office of the Rubber Replanting Aid Fund’s Staffs at statistically 0.05 significant level.

The purpose of this research was to study hot-melt adhesives from natural rubber (Standard Thai Rubber 20 STR 20). In order to improve the adhesion and melting properties of hot-melt adhesive to get the best glue formula from STR 20 the ethylene vinyl acetate content (EVA) paraffin wax (Wax) and petroleum resin (Resin) were varied from 25 50 100 125 and 150 phr (Part Per Hundred Rubber). It was found that the best adhesive formulas consisted of 100 phr of STR 20 25 phr of wax 150 phr of EVA and 150 phr of resin. For preparing hot-melt adhesive first the wax was heated and maintained at 160-170 ºC then cut the STR 20 into small pieces and slowly added the rubber into the melted wax until the rubber was completely melted. And then added resin and EVA and cooled to room temperature finally the results show that hot-melt adhesive was dark brown hard and odorless smooth texture and easy to melt with 514±14 centipoises of Viscosity at 150 ºC 82.49±1.4 lbf/in2 of shear strength and 2.06±0.02 kN/m of cleavage peel strength.

The objectives of this research are to study the rate of deterioration of tyre friction coefficient and investigate the quality of new and old tyres that are currently in use. A set of the rolling resistance testing was designed and set up to work with the single dynamometer according to speed 80 km/h tire load 4660 N and inflation pressure 30 psi. There were three tire samples new tire one year used tire and two year used tire to find the rolling resistance coefficients. The finding shows that the rolling resistance was inverse variation with tire aging. For instance the new tire (1st sample) had the highest rolling resistance on the other hand the two year used tire (3th sample) had the lowest rolling resistance. Moreover the rolling resistance coefficients were inverses variation with tire aging. Besides the one year used tire had the average of the decreasing rate of the rolling resistance coefficient at 0.03689 N/kN per a week while the two year had the average of the decreasing rate of the rolling resistance coefficient at 0.03671 N/kN per a week. Furthermore the result also revealed that the rolling resistance coefficients nonlinearly decreased comparing to the tire aging.

Properties of pumice aggregate mortar blended with para rubber wood fly ash (PRWFA) replaced type 1 ordinary Portland cement (OPC) in different proportions of 020 and 40 wt.% OPC and dosed with used engine oil (UEO) in proportions of 00.2 and 0.3 wt% water were investigated. Whole mix type specimens size was cast in 555 cm and curing in ambient temperature for 7 and 28 days. Testing series of physico-mechanical properties performed on bulk density water absorption electrical resistivity Shore hardness and compressive strength were determined. Moreover microstructure via scanning electron microscope was analyzed. Effect of curing ages enhanced properties of samples such as electrical resistivity Shore hardness and compressive strength. Particularly the 28-day specimen that contained 20wt.% PRWFA and 0.2wt.% UEO provided bulk density of 1.61 g/cm3 and highest compressive strength of 22.09 MPa.

The development of lightweight flat sheet prototype from para rubber leaves and para para rubber wood fly ash for field work application can offer an alternative method of adding value to agricultural wastes and help to conserve the environment with green products. The natural fiber especially agricultural waste fiber is an encouraging prospect. Natural fiber composites have been used for building applications. The aim of this research was to investigate the potential use of para wood ash to producing a cement composite as an environmentally material. Material. The cement paste with 5-2 % weight of para wood ash. The specimens were cured at 25± 2 oc for 24 hours. The properties of cement composites mixed with different proportions of para wood ash were compared with Ordinary Portland Cement (OPC). In addition the morphology of para wood ash was examined by using scanning electron microscope. The density increased with the increase in the percentage of para rubber leaves from 1% 2% 4% and 6%. The finding is attributable to the enhanced packing density by the fine para wood ash particles size was found 5-10 um.Moreover para wood ash particles could arrange to fill the inter-particle voids in cement pastes which resulting to increase the compressive strength of cement paste. Consequently para wood ashes could incorporate in the construction materials to enhance the mechanical properties and durability performance of the cement composites