Modification of tensile and impact properties of crosslinked rubber toughened nanocomposites via electron beam irradiation

Enhancing the tensile and impact properties of high density polyethylene (HDPE)/ethylene propylene diene monomer (EPDM) matrix is the main target of developing nanocomposite. The nanocomposite system was first prepared via melt intercalation method with different organophilic montmorillonite (OMMT) loadings. Electron beam (EB) irradiation was applied as a crosslinking agent for modification of tensile and impact properties of HDPE/EPDM matrix and HDPE/EPDM filled OMMT systems. The effectiveness of EB irradiation technique were then compared with control one (uncrosslinked system) and analyzed based on the tensile and impact tests as well as morphological xamination. The tensile and impact tests revealed that control and EB irradiated systems had attained the optimum tensile and impact properties at 4 vol% OMMT content. EB irradiated system at dose rate of 100 kGy showed excellent in tensile and impact properties with the highest rosslinking degree which were proved by gel content analysis. X-ray diffraction (XRD) analysis confirmed the existence of delamination structure with EB irradiation technique based on the disappearance of characteristic peak. The degree of delamination was further investigated by transmission electron microscope (TEM)

Ductile-brittle transition temperature of polylactic acid-based biocomposite

Almost all materials exhibit sensitivity of mechanical properties to temperature. Polylactic acid (PLA), an amorphous polymeric material, also exhibits this type of behavior. Because of its limited application in structural purpose, very few journals and articles study the ductile–brittle transition temperature (DBTT) of polymeric materials, especially PLA. It is necessary to determine DBTT to avoid brittle and catastrophic failure. This article determined the ductile-to-brittle transition of various PLA-based biocomposite. A comprehensive database was developed to determine the DBTT of PLA, PLA-20KF, PLA-20KF-5Clay, and PLA-5Clay. Impact tests were carried out on unnotched standard specimens at temperatures ranging from �5 � C to 28� C. The result shows that higher percentage of filler namely PLA-20KF and PLA-20KF-5Clay show lower impact strength and no significant decrease in impact strength with temperature. In contrast, lower percentage of filler such as PLA and PLA-5Clay shows better impact strength and comparatively sharp decrease in impact strength with temperature. Dynamic mechanical analysis (DMA) and fractographic analysis confirmed these statements that brittle fracture was observed in higher percentage of filled biocomposites whereas comparatively ductile fracture in lower percentage of filled biocomposites

Ductile-brittle transition temperature of polylactic acid-based biocomposite

Almost all materials exhibit sensitivity of mechanical properties to temperature. Polylactic acid (PLA), an amorphous polymeric material, also exhibits this type of behavior. Because of its limited application in structural purpose, very few journals and articles study the ductile–brittle transition temperature (DBTT) of polymeric materials, especially PLA. It is necessary to determine DBTT to avoid brittle and catastrophic failure. This article determined the ductile-to-brittle transition of various PLA-based biocomposite. A comprehensive database was developed to determine the DBTT of PLA, PLA-20KF, PLA-20KF-5Clay, and PLA-5Clay. Impact tests were carried out on unnotched standard specimens at temperatures ranging from -5°C to 28°C. The result shows that higher percentage of filler namely PLA-20KF and PLA-20KF-5Clay show lower impact strength and no significant decrease in impact strength with temperature. In contrast, lower percentage of filler such as PLA and PLA-5Clay shows better impact strength and comparatively sharp decrease in impact strength with temperature. Dynamic mechanical analysis (DMA) and fractographic analysis confirmed these statements that brittle fracture was observed in higher percentage of filled biocomposites whereas comparatively ductile fracture in lower percentage of filled biocomposites