Mechanical Properties of Chemically Treated Sawdust-Reinforced Recycled Polyethylene Composites
(11124–11129)  Industrial & Engineering Chemistry Research 50 #18 (2011)
Islam and Islam of Bangladesh University of Engineering and Technology, India, prepared cetyltrimethylammonium bromide (CTAB)-treated sawdust-reinforced recycled polyethylene (RPE) composites by injection molding.  The tensile strength (TS) values of the CTAB-treated composites were found to be much higher than those of the untreated ones. The Young’s modulus (YM), flexural strength (FS), flexural modulus (FM), and hardness values were also found to be improved for the treated sawdust–RPE composites compared to those of the untreated ones.  The tensile fracture surface morphological features of treated sawdust–RPE composites observed by scanning electron microscopy (SEM) revealed less microvoids and fiber agglomerates, indicating that better fiber–matrix interfacial adhesion has occurred upon treatment of the sawdust with CTAB. Water absorption (%) values were found to increase with increases in fiber content in the composite. However, treated sawdust–RPE composites showed lower water uptake capacity compared to those prepared from untreated sawdust. From the IR spectra of raw and treated sawdust together with water absorption behavior of the composite specimens, it appeared that surface treatment with CTAB significantly reduced the hydrophilic nature of sawdust, resulting in improved fiber–matrix interfacial adhesion.  (RDC  10/3/2011)

Effects of matrix molecular weight on structure and reinforcement of high density polyethylene/mica composites
(377-389)  Chinese Journal of Polymer Science 29, #2 (2011)
Chen et al ofSichuan University, China, studied high, medium and low molecular weight HDPE resins to evaluate the influence of matrix molecular weight on the structure-property relation of injection-molded HDPE/mica composites.  The transcrystallization of HDPE on the mica surface was observed and it exhibited strong matrix molecular weight dependence.  Obvious transcrystalline structure was found in the composite with low molecular weight HDPE, whereas it was hard to be detected in the composites with increased HDPE molecular weight. The best reinforcement effect in the composite with low molecular weight HDPE can be understood as mainly due to substantially improved interfacial adhesion between matrix and mica filler, which arises from the transcrystallization mechanism.  (RDC 4/13/2011)