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.

Poly (1,4-dioxan-2-one)(PPDO)/starch blend is a novel biodegradable polymer system, and it has potential applications in preparing various low-cost environmentally friendly materials. In order to understand the relationship between their structure and properties, the thermal transition, crystallization and spherulitic morphology of PPDO/starch blends have been studied by means of differential scanning calorimetry (DSC) and polarized optical microscopy. It was found that when 5wt% starch was added to PPDO, a clear nucleating effect was observed. When the blends were crystallized from the melt, they formed banded spherulites that exhibited a well-defined Maltese cross depending on the crystallization temperature. Avrami exponents and crystallization rate constants of the blends with 5wt% starch were higher than those of PPDO and those of the blends with 10wt% starch. Both the dynamic DSC results and isothermal crystallization data indicated that the starch, with a content of 5wt% in the blends, acted as the nucleating agent for PPDO.

Potassium diphenyl sulfonate (SSK), poly-(sulfonyl phenylene phosphonate) (PSPPP), and their mixtures are proved to be effective flame-retardants for polycarbonates (PCs) by measuring the limited oxygen index values and UL-94 of blends. The flame-retardant systems are characterized by thermogravimetric analysis under dynamic conditions. The resulting data, together with the analysis of the activation energies, demonstrates that the additives ac-celerate thermodegradation, especially in the early stage, and different additives cause a different process in the final stage.

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.

Poly (p-dioxanone)(PPDO)/montmorillonite nanocomposites were prepared through the in situ ring-opening polymerization of p-dioxanone (PDO) and three types of montmorillonites (natural sodium montmorillonite, montmorillonite modified by octadecyltrimethyl ammonium chloride, and montmorillonite modified by hydroxyethylhexadecyldimethyl ammonium bromine) in the presence of triethylaluminum. Montmorillonite could accelerate the polymerization of PDO, and the viscosity-average molecular weight of PPDO could reach 44,900g/mol in 0.5h. A nucleating effect of montmorillonite was observed, and the crystallization temperature of PPDO was increased by 18 8C. All three montmorillonites could improve the thermal stability of PPDO and increase the glass-transition and melting temperatures of PPDO.