Synthesis And Properties Study Of The Poly (Dodecanedioic Acid Pentylene Glycol) And Its Copolymers

In recent years, the research about biodegradable polyester materials has become a hot topics because of their good degradation performance, and some polymers have begun industrial production. Among the biodegradable polymers, the aliphatic polyesters are studied much, but they generally have low melting point, poor mechanical properties and higher production costs. These factors restrict the development of the aliphatic polyester. In this work, a new aliphatic polyester and its copolymers were prepared and its properties were studied in detail.Using dodecanedioic acid and 1,5-pentanediol as raw materials, poly(dodecanedioic acid 1,5 neopentyl glycol)(PDAPG) were prepared by melt-polycondensation method; secondly, by adding dimethyl terephthalate(DMT) or succinic anhydride(SAA) instead of part of dodecanedioic acid, some aliphatic and aromatic copolyester was synthetized; on the other hand, by adding the modified halloysite(HNTs) to the system, a HNTs/PDAPG composite material was prepared by in situ polymerization method. The materials' properties were characterized by Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance hydrogen spectrum method(1H NMR) and gel permeation chromatography(GPC), differential scanning calorimetry(DSC), and thermogravimetric analyzer(TG A), polarizing optical microscopy(POM), and X-ray diffraction(XRD).The results suggest that the polyester with high molecular weight can be synthesized by melt polycondensation method, and it has good crystallization properties. The average molecular weight is 5.72×104 g/mol and the crystallization degree can reach 69.3% when the product was cooled from melt. The glass transition temperature of the amorphous polyester is about-46.1oC. After buried 3 months in the northern soil in summer, the biodegradation experiment showed that the sample destroyed from rectangle sample into fragment, and its color changed from white to yellowish with decreased weight. The copolyesters synthesized with DMT have lower melting points and melt-crystallization temperature, and the thermal stability was also decreased slightly. Its glass transition temperature increased with increasing DMT content. The copolyesters synthesized with SAA have large molecular weight(8.71×104 g/mol), and their melting points, melt-crystallization temperature and thermal stability are decreased with increasing SAA content. XRD ray diffraction results showed that the the copolyesters has similar crystals with that of PDAPG. HNTs/PDAPG composite materials have similar melting points, melt-crystallization temperature, but their crystals are much smaller than that of PDAPG. The storage modulus is increased with increasing HNTs content in composites, suggesting that HNTs has some reinforcing function to PDAPG.