Studies On The Anti-dripping Modification Of Polyester Fiber By Blending Silicon Resin

Polyethylene terephthalate(PET)has been widely applied as a textile and industrial material owing to its high strength, high rigidity, excellent heat resistance and dimensional stability etc. However, PET fiber is thermoplastic and flammable. When burning, they tend to form melting drops, which not only can result in other damages, but also transmit burning flame to the other substance. So the studies on the modification of PET fibers for improving the property of anti-dripping have become a research direction. In order to enhance the anti-dripping property, the approaches adopted are to blend some additives (such as PTFE, phyllosilicates etc.), which can improve the melt viscosity. Besides, copolymerization method is also applied. However, the means will lead to spinning difficulty.In this thesis, a thermoplastic silicon resin copolymer, MMA polymerized with KH570, is blended with PET, and then PET/silicon resin fiber was prepared. The fluidity was obtained through MMA and the anti-dripping property was obtained through KH570. In the paper, the reaction character of copolymerization, the rheological properties of PET/silicon resin and the properties of PET/silicon resin fibers were studied by viscosimeter method, FT-IR, melt flow rate indexer, RH-7 Capillary Rheometer, SEM, XRD, TG, DSC and anti-dripping tests.The thermoplastic silicon resin copolymer was prepared through bulk polymerization. The relation between transform rate and initiator concentration, polymerization temperature, polymerization time, different initiator, monomer ratio were studied by weight method. It showed that the rate of polymerization and the transform rate increase with increase of initiator concentration, polymerization temperature and the ratio of the MMA in the monomer. The viscosity of the copolymer was studied by Ubbelohde viscosity meter. It showed that the viscosity of the copolymer decreased with the increase of initiator concentration or polymerization temperature. The structure of copolymer was charactered by FTIR and the thermal property and fluidity was studied by TG and melt flow rate indexer. Contrast with the fluidity of PET, the best reaction condition was obtained: 0.8%AIBN,reaction temperature 45℃and reaction time 1.5hour.The rheological properties of PET, PET/ silicon resin were investigated by melt flow rate measurer and RH-7 Capillary Rheometer. Results indicated that the melt index of PET/silicon resin decreased with the increase of the silicon resin ratio; the apparent viscosity gradually decreased with the temperature or shear rate increase, melts showed non-Newtonian pseudo-plastic fluid characteristics, and the non-Newton index(n)increased with the increase of temperature. But the structural viscosity index and the zero shear viscosity decreased. The activation energy and apparent viscosity decreased with the increase of the shear rate. In this thesis, the influence of the silicon resin ratio on the rheological properties of PET/silicon resin was also studied. With the increase of the silicon resin ratio, the structural index increased and the non-Newton index(n)and the activation energy decreased.The surface morphological structure and crystal structure of anti-dripping polyester fibers were charactered by SEM and XRD. Results showed that the surface of anti-dripping polyester fibers surface was similar to traditional pure polyester fibers. XRD indicated that the crystal structure of the PET/ silicon resin fibers was not changed with the addition of silicon resin. The crystallinity decreased to 26% when the ratio of silicon resin was 5%.The thermal decomposition of anti-dripping PET fiber contained two stages: the thermal decomposition of silicon resin and polyester fiber; DSC showed that the melting point of anti-dripping polyester fibers was lower than that of pure PET fiber. KES-G1showed that the tensile strength of anti-dripping PET fiber was 129Mpa, a little lower than that of pure PET fiber. The melting drops number of the anti-dripping PET fiber decreased, which show that the approach proposed is viable.