بررسي خواص حرارتي و مكانيكي چندسازه الياف بذري استبرق/پلي‌پروپيلن

Investigation on mechanical and thermal properties of giant milkweed (Calotropis persica) fibers -plastics composites

در اين بررسي امكان استفاده از الياف استبرق در ساخت چندسازه الياف طبيعي به‌همراه پلي‌پروپيلن مورد توجه قرار گرفت. اثرات درصد الياف در چهار سطح (10، 20، 30 و 40 درصد) و جفت‌كننده مالييكي (MAPP) در سه سطح (صفر، 5/1 و 3 درصد) بر خواص مكانيكي و حرارتي چندسازه چوب پلاستيك بررسي شد. نتايج آزمايش‌ها نشان داد كه استفاده از MAPP باعث بهبود خواص مكانيكي در جريان مخلوط سازي در فاز درون سطحي شده و سبب اتصال بهتر بين الياف و ماتريس و ترشوندگي بهتر الياف در حضور جفت‌كننده گرديد. تجزيه و تحليل رفتار حرارتي فرآورده مركب نيز به كمك آزمون HDT نشان داده است كه استفاده از 3 درصد MAPP به‌همراه 30 و 40 درصد الياف استبرق باعث افزايش مقاومت حرارتي چندسازه نسبت به ساير تيمارها شد.

The suitability of using Iranian grown giant milkweed fibers (GFs) as a new raw material for thermoplastic composites was investigated. The polypropylene (PP) was used as the matrix polymer and the maleated polypropylene, Epolene G- 3003TM, was used as coupling agent. In the sample preparation, four levels of fiber loading (10, 20, 30, and 40 wt%) and three levels of coupling agent content (0, 1.5, and 3 wt%) were applied and the mechanical properties of composites are analyzed. GF/PP composites were prepared by a melt compounding process in a twin-screw extruder followed by injection molding. The results showed that with the addition of coupling agent, both tensile and flexural properties improved considerably compared with control specimens (without coupling agent). As expected, notched Izod impact strength was significantly decreased as the mixing ratio of fiber increased. The results of the present study revealed that composites with good strength properties could be successfully developed using GF as the reinforcing agent. The Heat Deflection Temperature (HDT) is determined following the test procedure outlined in ASTM. High HDT in this study showed that coupling agent at3 wt% and fiber loadiny either 30 or 40 wt% were superior compared with other treatments.