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 work was to study the improvement of toughness and impact resistance of polylactic acid (PLA) with modified soybean oil (MSBO) and palm fiber (PF). The detail of this work was divided into three parts. The first was to find the suitable condition for modification of soybean oil with ozonolysis. The second and last parts were to study the effects of MSBO and PF contents on the properties of PLA respectively. For oil modification the reaction times were varied from 0 to 3 hours and the chemical changes in molecules of soybean oil were investigated by Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies. The result suggested that the most suitable condition for ozonolysis reaction was 2 hours considering the decrease in double bond between carbon atoms and the increase in hydroxyl group into molecular structure of MSBO. For the effect of MSBO content on mechanical properties it was evaluated by tensile and impact testing. Differential scanning calorimeter (DSC) and scanning electron microscope (SEM) were used for thermal and morphology analyses. The result showed that elongation at break and impact strength of modified PLA by MSBO increased about 89 and 25 % compared to those of neat PLA respectively. MSBO act as the efficient plasticizer for PLA considering the conversion of fracture behavior from brittle to ductile good dispersions of MSBO droplets in PLA and the decrease of glass transition temperature (Tg) with addition of MSBO. The addition of PF improved the impact strength of modified PLA. Strong interfacial bonding between PLA and PF indicated MSBO being both coupling agent for PLA and natural fiber and plasticizer for PLA. For migration test it was found that contents of released heavy metal and migrated chemical from specimens of PLA and PLA/PF composite were under the criteria according to Notification of the Ministry of Public Health (No. 295) B.E. 2548.

The purposes of the research were to create and find out the efficiency validation of computer assisted instruction focused on the Plastic Injection Adjusting Machine and Injection Molding Maintenance for the standard 90/90 and to analyze the students’ learning achievement after using computer assisted instruction. The samples were 20 first year diploma tool & die students at Rajamangala Institute of Technology North Bangkok Campus. The students pretested and then studied by using the computer assisted instruction focus on the plastic Injection Adjusting Machine and Injection Molding Maintenance. Finally the students post tested. After that the data was calculated to find out the computer assisted instruction efficiency and analyzed the students’ learning achievement after studying. The result revealed that the computer assisted instruction efficiency was reached the standard 90/90 and the students’ learning achievement increased significantly at 0.05.

Comparing the shrinkage values of HDPE 2 – 4 % that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 1.1 Comparing the shrinkage of the specimen with 2 mm. thick The result showed that the shrinkage between at the point nearby the entrance is different from at the point further from the entrance and it is also different from the limited value from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. Comparing the shrinkage values of PET 0.2 - 0.4% that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 1.2 Comparing the shrinkage of the specimen with 2 mm. thick The finding revealed that the shrinkage value between the point nearby the entrance and the point further from the entrance are different but the same as the limitation from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but the same as the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The finding revealed that the shrinkage value of the follow injection the across injection and the limited value from the manufacturer are the same. Both comparing HDPE and PET have statistical significance at 0.05