The solubility behaviors of poly(sulfonyldiphenylene phenylphosphonate) (PSPPP), a very efficient flame retardant for poly(ethylene terephthalate) (PET), in more than 50 solvents were examined. Its solubility parameters (δ) were determined by the intrinsic viscosity and turbidic titration methods. The two methods obtained consistent results, δ=21.0-21.6J1/2/cm and δ=21.0J1/2/cm3/2, and the three-dimensional solubility parameters were δ=18.9J1/2/cm3/2, δ=8.8J1/2/cm3/2, and δh=5.9J1/2/cm3/2. The miscibility of PSPPP with PET was estimated by the calculation of the heats of mixing, which were related to the difference between the solubility parameters of PSPPP and PET. Fourier transform infrared was used to examine the interactions between PSPPP and PET macromolecules, which were the internal factors of polymer-polymer miscibility. The results showed that PSPPP and PET were miscible within a very wide composition range, especially with less than 15wt% PSPPP, a composition of interest for the preparation of flame-retardant PET.

To obtain a biodegradable polymer material with satisfactory thermal properties, higher elongation and modulus of elasticity, a new copolyester, poly(butylene succinate-co-ethylene succinate-co-ethylene terephthalate) (PBEST), was synthesized via direct polycondensation from three prepolymers of butylenes succinate, ethylene succinate and ethylene terephthalate (ET). The resulting copolyesters, PBEST, were characterized by 1H-NMR, DSC, TG and WAXRD, and their melting temperature (Tm), melting heat of fusion (DHm), glass-transition temperature (Tg), and thermal decomposition temperature (Td) (1.5wt%) were obtained. Compared to poly(butylene succinate-co-ethylene succinate) (PBES), PBEST has improved thermal properties such as higher Tm and Td due to the incorporation of poly (ethylene terephthalate) unit into the main chains of copolyesters, but very low crystallization speeds. The degradation test of copolyesters in a compost condition shows that the degradability of PBEST is as a function of content of ET.

The combination of two modification techniques developed for the ZSM-5 zeolite, i.e., desilication and incorporation of lanthanum under microwave irradiation, has produced a highly efficient catalyst, DeLaZSM-5, for catalytic degradation of low-density polyethylene (LDPE). Its performance on the degradation was studied at 390C and compared with the parent ZSM-5 and the modified intermediate products desilicated ZSM-5 (DeZSM-5) and LaZSM-5. Among the catalysts tested, DeLaZSM-5 showed the highest catalytic degradation rate. In addition, on DeLaZSM-5 the liquid yield was slightly increased and the isoparaffin index of the liquid was almost doubled, which indicated higher liquid quality compared with the parent ZSM-5 zeolite. The high catalytic activity of DeLaZSM-5 could be explained by its unique acidic properties with a sharp increase of the number and strength of weak acid sites and a decrease of strong acidsites.

The thermal transition, crystallization and spherulitic morphology of starch-g-poly (1,4-dioxan-2-one) copolymers were studied by means of differential scanning calorimetry (DSC) and polarized optical micrographs (PM). It is found that the graft structures of copolymers have obvious effects on the thermal and crystallization behaviors. Because there were more defect sites in the crystalline phase originating from the short grafted chains of poly (1,4-dioxan-2-one)(PPDO), the crystal structure of the copolymers was much less perfect than that of PPDO. PM revealed that the spherulitic morphology of the graft copolymers depended on graft structures and crystallization temperatures. From the single polarized micrograph of the graft copolymers it was observed clearly that the starch segments acted as nucleation sites. The Avrami equation was used to analyze the overall isothermal crystallization of the graft copolymers. Avrami exponents were almost constant at crystallization temperatures Tc ranging from 45 to 60 8C. Both the PM observation and the DSC investigation (crystallization rate constant, K values) indicated that the graft copolymers crystallize faster than pure PPDO, especially at higher crystallization temperatures.