The Preparation Of Vinyl Chloide Copolymer Elastomer And Study On Application In Modification Of UPVC

Due to the presence of relatively high polar groups in the molecular structure of PVC, the force between the PVC molecular chains is very high, making the molecular chains of PVC a rigid structure. As a result, the impact resistance and processability of the Unplasticized Polyvinyl Chloride (UPVC) are poor, which limit the processing and application of UPVC. For a long time, in order to improve these defects of PVC, adding toughening modifiers such as ACR, CPE, MBS, etc., into PVC or grafting other molecular chain segments on PVC molecular chain segments have been widely used. In this paper, vinyl chloride copolymer elastomer (VCE) was synthesized with raw materials such as vinyl chloride, butyl acrylate, methyl methacrylate by suspension polymerization. The structures and properties of VCE, the modification effects of VCE as toughening modifiers on UPVC and the final application of VCE in the UPVC molding process were studied. The main research contents of the article were as follows:1. The structures of the copolymer were investigated by means of Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR). It was proved that the synthetic product was the copolymer of three monomers rather than a mixture of them. The particle morphology of the copolymer elastomer was observed by Scanning Electron Microscope (SEM), the molecular weight of the copolymer elastomer was tested by Gel Permeation Chromatograph (GPC), the glass transition temperature of the copolymer elastomer was characterized by Differential Scanning Calorimetry (DSC), the thermal stability of the copolymer elastomer was characterized by Thermo-Gravimetric Analyzer (TGA), the intrinsic viscosity of the copolymer elastomer was tested by Ubbelohde Viscometer, the mechanical properties of the copolymer ealstomer were also tested and analyzed. According to the results, it was found that the novel elastomer had many excellent properties such as thermal stability, toughness and processability, thus having a bright application prospect.2. The modification effects of VCE as toughening modifiers on UPVC were studied and the relationships between the properties of UPVC and VCE types and VCE dosage were analyzed. The research results showed that the mechanical and processing properties of UPVC which had been modified by VCE were significantly improved; especially the impact property of UPVC modified by VCE in low-temperature was greatly improved. VCE played a significant role in toughening UPVC, indicating that it could be used as a toughening modifier in the processing of UPVC.3. The comparative analysis of properties between UPVC modified by VCE and UPVC modified by traditional toughening modifiers were studied. In the light of the comparative results, it was known that the properties of UPVC modified by VCE were very close to the properties of UPVC modified by ACR when the dosage of VCE and ACR were the same. The modification effects of 1 phr VCE on UPVC were nearly equal to the modification effects of 2 phr CPE on UPVC. In addition, the modification effects of the mixed system of VCE and CPE on UPVC were also studied. The results showed that the less VCE propotion and the more CPE propotion of the mixed system, the worse the mechanical properties and hardness of UPVC modified by the mixed system. Thus it was supposed that VCE could be applied in the molding and processing of UPVC as a potential substitute for traditional toughening modifiers.4. The project that VCE, which replaced CPE (4 phr VCE replaced 8 phr CPE) as a toughening modifier, was used in the production of UPVC pipe was studied. The UPVC pipes were successfully producted, and the properties of UPVC pipes were measured. The results showed that the properties of UPVC pipes completely met the standard of the enterprise; especially some properties such as the appearance, the glossiness and the tensile yield strength of UPVC pipes were more excellent. It was inferred that VCE could be applied in the production of UPVC pipes and completely replaced CPE as toughening modifiers.