| Poly(p-dioxanone) (PPDO), as a well-known aliphatic polyester with good physical properties and outstanding biocompatibility, biodegradability, bioabsorbability, has been used to make monofilament sutures with good tenacity and knotting. It has ultimate biodegradability, because of the ester bonds in polymer chains, and the unique ether bonds endue it with good flexibility. As there are many microorganism in nature, which can made PPDO to be degraded, PPDO is also a good candidate for general uses such as packet films, mold products, laminates, foams, non-woven materials, adhesives, and coatings. However, it is difficult to get high molecular weight PPDO, because of highly request on monomer purity, long time for ring-opening polymerization, strict synthesis conditions and so on. Polyester of succinate, as one of aliphatic polyester with good thermal stability, is cheaper than PPDO. Researchers take focus on it, for its good processability, elasticity and strength, which make it to be a potential universal material. But there also has many troubles to be resolved, such as the very high temperature and vacuum, low molecular weight of products, strict demand on the chemical gauge of tow monomers, and so on. In order to resolve those problems, lower its cost and widen its uses, we use chain-extending reaction to link PPDO and poly(ethylene glycol succinate)/poly(butanediol succinate) (PES/PBS) with low molecular weight. In this paper, chain-extending products of PPDO and PES/PBS (PPDOES/PPDOBS) was synthesized by chain-extending reaction, using toluene-2,4-di-iso-cyanate (TDI) as a chain extender. Several instruments such as infrared (IR), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), wide-angle-X-ray diffractometry (WAXD), hot-stage polarizing optical microscope (PM) and thermogravimetry analysis (TG) have been employed to investigate the structure-properties relationship of chain-extending products.Different reaction time, reaction temperature and the ratio of prepolymer and chain-extender have been studied in chain-extending reaction of PPDO and PES/PBS. The investigation shows that the ratio of prepolymer and chain-extender has the most important influence on the inherent viscosity of chain-extending products. The chain-extending products can achieve a very high inherent viscosity only while the ratio of prepolymer and chain-extender at the most suitable point. The structures of chain-extended products have been confirmed by 1H-NMR and IR spectra.TG, PM, DSC and WAXD have been utilized to investigated the thermal properties, crystallization behaviors and morphology of chain-extended products. The results of thermal oxidative degradation show that chain-extended products have better thermal stability than PPDO. And the thermal degradation of chain-extended products shows two stages, the first stage was due to the degradation of PPDO segment of chain-extended products, and the second stage was the degradation of PES/PBS segment. DSC measurement showed that each chain-extended product has only one Tg. That is to say PPDO has very good compatibility with PES/PBS. The crystallization phenomenon of chain-extended products PPDOES was just like that of PES, due to the existing PES segment in PPDOES; and its Tg and Tm increased with the increase PES contents in PPDOES. PPDOBS has two crystalline peaks during the cooling scan, suggesting that PPDO segment and PBS segment has their own crystalline region. And it has crystallized completely due to none crystalline peak during the heating scan. The diffraction peaks of the chain-extended product appear at the same 2θ angles as that of homopolymers, suggesting that the PPDO and PES/PBS of the chain-extended product reserve their own crystalline form. PPDOES can also develop well-defined spherulites with a clear Maltese cross and bands while cooling from the melt. The crystal growth rate of PPDOES is quite slow comparing with what of each homopolymer, due to the influence of PPDO segment and PES segment on each other. The spherul...
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