Synthesis and Properties of Polybutylene (Succinate)-b-poly(dimethylsiloxane) with Unprecedented Combined Performance and Functions.

The excellent combined properties of poly(butylene succinate) (PBS) make it a promising biodegradable plastic. However, the lack of functionality and low impact strength limit its application. Poly(dimethylsiloxane) (PDMS) was introduced to prepare new high-performance and functional poly(butylene succinate)-b-poly(dimethylsiloxane) (PBS-b-PDMS) in this work. The resulting PBS-b-PDMS was found to possess high molecular weight, narrow molecular weight distribution, and excellent combined performance. PBS-b-PDMS had good thermal properties. The decomposition temperature of 5% weight loss (T5%) increased from 324 to 344 °C, and the temperatures at the maximum weight loss rate (Tmax) values increased from 385.1 to 396.7 °C. The impact strength increased significantly from 7.8 kJ/m2 of PBS to 53.9 kJ/m2 of PBS-b-PDMS. As the PDMS block endows copolymers with low surface energy and good liquid resistance, PBS-b-PDMS has excellent antismudge, self-cleaning, and solvent resistance. Finally, to minimize the surface energy, PDMS blocks preferentially enrich the surface, which imparts the polymers with self-cleaning properties.

A Non-Isocyanate Route to Poly(Ether Urethane): Synthesis and Effect of Chemical Structures of Hard Segment.

A series of non-isocyanate poly(ether urethane) (PEU) were prepared by an environmentally friendly route based on dimethyl carbonate, diols and a polyether. The effect of the chemical structure of polyurethane hard segments on the properties of this kind of PEU was systematically investigated in this work. Polyurethane hard segments with different structures were first prepared from hexamethylene di-carbamate (BHC) and different diols (butanediol, hexanediol, octanediol and decanediol). Subsequently, a series of non-isocyanate PEU were obtained by polycondensation of the polyurethane hard segments with the polyether soft segments (PTMG2000). The PEU were characterized by GPC, FT-IR, 1H NMR, DSC, WAXD, SAXS, AFM and tensile testing. The results show that the urea groups generated by the side reaction affect the degree of crystallization of hard segments by influencing the hydrogen bonding of the hard segments molecular chains. The degree of hard segment crystallization, in turn, affects the thermal and mechanical properties of the polymer. The urea group content is related to the carbon chain length of the diol used for the synthesis of hard segments. When butanediol is applied to synthesize hard segment, the hard segment of the resulting PEU is unable to crystallize. Therefore, the tensile strength and modulus of elasticity of butanediol-based PEU is lowest among three, though it possesses the highest urea group content. When longer octanediol or decanediol is applied to synthesize the hard segment, the hard segments in the resulting polyether-based polyurethane are crystallizable and the resulting PEU possesses higher tensile strength.