Biến đổi cấu trúc và tính chất của vật liệu compozit polyetylen tỷ trọng cao/bột gỗ gia cường bởi hạt nano TiO2 sau thử nghiệm gia tốc thời tiết

In this study, the composites based on high density polyethylene (HDPE) and wood flour (WF) in the presence of PEgMA compatibilizer and TiO2 nanoparticles (in rutile crystal form) were investigated the accelerated weathering test. After 1.900 hours testing, tensile strength of HDPE/WF composite using PEgMA reduced siginificantly (remaining value of 55.98 %). Whereas, the mechanical properties of the HDPE/PEgMA/WF composites slightly decreased thanks to the presence of TiO2 nanoparticles, the retention of tensile strength of composite using TiO2 of 3 wt.% is 81.89 %. Calculating from Fourier transform infrared (FT-IR) spectra showed that the carbonyl index (CI) and wood index (WI) of composites without TiO2 were higher than that of composites containing TiO2. Besides, the discoloration of HDPE/PEgMA/WF composite could lead to lightening on the surface, in fact, this occurs clearly in the case of composites containg TiO2 in comparison with the sample without it. It may imply that TiO2 nanoparticles played a role as the degrading inhibitors of composites under UV irradiation. In addition, observation from the SEM images, the surface of HDPE/PegMA/WF/TiO2 composites was detroyed less than that of composites without TiO2

Độ bền dai tách lớp và tính chất cơ học của vật liệu polyme compozit trên cơ sở nhựa epoxy epikote 828/OELO gia cường sợi cacbon, đóng rắn bằng xyanetyldietylentriamin

Carbon fabric/epoxy (CF/EP) composite toughened by OELO was prepared to improve fracture toughness of the composite. The obtained testing results showed that the Izod impact strength of carbon fabric/epoxy composites significantly increased by 31.4 % from 37.2 KJ/m2 to 48.9 KJ/m2 just by adding 6 phr (part per hundred of resin) OELO was dispersed in the epoxy matrix. Both mode-I interlaminar fracture toughness of carbon fabric/epoxy (OELO/EP) composites at crack initiation and propagation also improved by 37.2 % and 17.7 %, respectively by content of 6 phr OELO in compositions. Damaged surfaces of fractured samples were investigated using scanning electron microscopy (SEM) techniques. Results obtained from dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperatures of the epoxy resin matrix were slightly reduced on the addition of 6phr OELO. Keywords. Epoxy resin, fracture toughness, epoxidized linseed oil oligomer, composite materials