In order to improve the performance of inorganic/organic composites, aluminum trihydroxide (ATH) core composites with a styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (MAH‐g‐SEBS) shell phase, and P‐N flame retardant as a synergistic agent, were prepared through an interface design. The effects of polyethylene glycol (PEG) content on the interfacial interaction, flame retardancy, thermal properties, and mechanical properties of high‐density polyethylene (HDPE)/ATH composites were investigated by small angle X‐ray diffraction, rotational rheometer, limiting oxygen index, thermogravimetric analysis (TGA), and tensile testing. The ATH synergistic effects of P‐N flame‐retardant improved the combustion performance of HDPE/ATH/PEG(3%)/MAH‐g‐SEBS/P‐N (abbreviated as HDPE/MH3/M‐g‐S/P‐N) composite by forming more carbon layer, increased the elongation at break from 21% to 558% compared to HDPE/ATH, and increased the interface thickness from 0.447 to 0.891 nm. SEM results support the compatibility of ATH with HDPE increased and the interfacial effect was enhanced. TGA showed the maximum decomposition temperature of the two stages and the yield of the residue at high temperature increased first and then decreased with the increase of PEG content. Rheological behavior showed the storage modulus, complex viscosity, and the relaxation time initially increased and then decreased with the increase of PEG content indicating PEG, M‐g‐S, and ATH powder gradually formed a partial coating, then a full coating, and finally an over‐coated core‐shell structured model.
High‐viscosity, low‐crosslinked poly(butylene terephthalate) (PBT) from organic chain extenders and inorganic particles are prepared. PBT modification adopted from multifunctional, commercially available chain extension containing nine epoxy groups (ADR9) occurs in the first‐step chain extension; hydroxyl addition modified dioxazoline (BOZ) serves as the second step. Anion stratiform inorganic hydrotalcite (HT) is used to adjust the crystallization behavior and damp‐heat aging properties of PBT. The reaction between the chain extender and PBT end‐groups such as carboxyl (–COOH) and hydroxyl (–OH) enhances the interfacial bonding between the PBT matrix and dispersed HT phases. With a fraction of chain extenders in the PBT matrix, the chain‐extended PBT exhibits higher mechanical properties, intrinsic viscosity, average molecular weight, and melt viscosity than those of unmodified PBT. Damp‐heat aging resistance measurements show correlation with initial carboxyl content in the resin. Reducing the concentration of carboxyl end‐groups in the resin is shown to increase hydrolytic stability. The modified PBT resin can be used in optical fiber communication cable industry for its high level of damp‐heat aging resistance as well as good mechanic properties.
The use of glycidyl methacrylate (GMA) and acrylic acid (AAc) as grafting monomers to improve the mechanical properties, particularly tensile strength, of recycled polyethylene (R-PE) is reported in this study. The AAc monomer was implemented to improve the stability of radical chains which could undergo GMA grafting. When the content of GMA and AAc was 1.2% and 0.6%, respectively, the tensile strength increased from 17.26 to 29.3 MPa, the elongation at break increased from 107% to 647%, and the melt index decreased from 3.42 to 0.97 g/10 min. The sensitivity of the dynamic behaviour of R-PE-g-(AAc-co-GMA) to temperature was also reduced relative to R-PE. Differential scanning calorimetry (DSC) results showed that the melting temperature was increased and the crystallisation temperature of R-PE-g-(AAc-co-GMA) was reduced. The fracture morphology of the samples was also shown by scanning electron microscope (SEM) observations to transition from brittle fracture to ductile fracture upon undergoing the grafting process.
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