Modification And Environmental-friendly Improvement Of High-filled Polyvinyl Chloride

High-filled poly（vinyl-chloride） composite have been applied widely in industry due to the low-price,hardness, dimension stability and good resistance to heat and fire. In order to improve the mechanical properties and processability and comply with environmental requirements, PVC/CPE/CaCO₃、PVC/CaCO₃/KL and（SG-7/SG-5）PVC/CaCO₃ composites were made, and the mechanical properties, as well as the rheological properties were tested and characterized via test instrument such as torque rheometer, rotational rheometer, DMA, tensile test and impact test, besides, the environmental improvement of the high-filled poly（vinyl-chloride） composite were discussed and focused on the stabilizer and plasticizer.The mechanical properties of high-filled PVC/CaCO₃ composites were improved significantly by the addition of CPE from 0 phr（4.92 KJ/m2） to 10 phr（11.49 KJ/m2）,besides, the addition of CPE would lead to the decline of relaxation index t2 and Tg. Through analyzing the dynamic rheological behavior of the composites, it is inferred that a semi-encapsulated, fully-encapsulated, extra-encapsulated model appears between CPE and CaCO₃ particles, which explaining the toughening mechanism of CPE in the composites.With the increasing content of KL in PVC/CaCO₃/KL composites, the storage modulus G’ increased gradually and the λ decreased gradually, which implied the change of inner structure.The high content of KL increased the tensile strength and decreased the impact strength significantly. In low content of KL, the interaction between CaCO₃ and Kaolin is strong, in high content of KL, the interaction between CaCO₃ and PVC would be weakened as a new continuous phase of KL may formed. The tensile strength（9.87MPa）, elongation（21.52%） and impact strength of PVC/CaCO₃ composite（SG-7:SG-5is 60:40） is better than the PVC/CaCO₃ composite without SG-7（10.40 MPa,17.95%,1.99KJ/m2）. Besides, the balance torque, G’ and λ were decreased with the increasing content of SG-7, which indicated that the combination of SG-7 and SG-5 may contribute to good rheological properties and mechanical properties of the PVC/CaCO₃ composite.Processing plasticizing stability of the high-filled PVC/CaCO₃ will be improved at the low content of MT or Ca/Zn, and the stabilized effect of MT is better. Moreover, the addition of MT could decreased the Tg, and enhanced the mechanical properties to some extent, which is better than Ca/Zn. Compared with the plasticizer DOP, the TP lead to shorter plasticizing time, slight higher balance torque and nearly the same Tg. Since the high-filled PVC composites with TP and MT lead to better mechanical properties than that with DOP and PbSt2, TP/MT could be replaced by TP/MT to reach the environmental protection requirement.