Study On The Preparation And Properties Of PVC Nanocomposites

In order to enhance the processing property and impact strength of poly(vinyl chloride, PVC) product, the PVC was blended and modified with nanofillers, including cage-like methylacryloylpropyl silsesquioxane(MAP-POSS), acrylic core-shell copolymer(ACR), multiwalled cabon nanotubes(MWCNTs), graphene oxide(GO), and the PVC nanocomposites containing the nanofillers aforementioned were prepared. The plasticizing behavior, dynamic mechanical property, mechanical property, and the mophology of the impact fracture surface was measured and studied.1. A series of acrylic core-shell resins(ACR) with different amount of methylacryloylpropyl polyhedral oligomeric silsesquioxane(MAP-POSS) and core/shell ratio were synthesized and characterized by TEM and particle sizer. The dynamic mechanical properties of ACR and PVC/ACR blends were characterized by Dynamic mechanical analysis(DMA); the plasticizing behavior and mechanical properties of the blends were determined. The results show that MAP-POSS takes part in the grafting and cross-linking reaction in the core of the ACR; The shell has the highest glass transition temperature when the MAP-POSS content is 5 wt% and 10 wt%; The powder effect is better when the core/shell mass ratio is 1:1; The plasticizing time decreases while the plasticizing torque increases as the ACR content increases; The blends show the best impact resistance when ACR addition is 11 wt% of the matrix, which is 72.9 % higher than that contains no ACR.2. The methyl methacrylate-b-butyl acrylate-b- methyl methacrylate(MMA-b-BA-b-MMA, MBM) triblock copolymer was synthesized via reversible addition-fragmentation chain transfer(RAFT) emulsion polymerization and was blended with poly(vinyl chloride)(PVC). The plasticizing behavior and Dynamic mechanical properties were studied using torque rheometer and dynamic mechanical analyzer, and the mechanical properties were tested. The results indicate that MBM can efficiently reduce plasticizing time and balance torque; The storage modulus E￠ of blens decreases as the increasing MBM content. When the MBM content is 25 wt%, the Tg of blends is 71.9 °C, which is 5.2 °C higher than pure PVC; The tensile strenth is 35.79 MPa and the impact strength is 9.00 k J·m-2,which is 4.0 times than that cotains no MBM..3. Poly vinyl chloride(PVC)/Poly(acrylonitrile-styrene-acrylate)(ASA)/ multi-walled carbon nanotubes(MWCNTs) nanocomposites were prepared. The plasticizing behavior, dynamic mechanical properties, mechanical properties and thermal stability of the nanocomposites were studied. The results show that the plasticizing time shortens as the MWCNTs content increases. The nanocomposites show the best impact strength, which is 83.7 % higher than pure PVC/ASA blend, when the MWCNTs content is 0.054 wt%. MWCNTs can enhance the thermal stability of PVC/ASA blends, the initial decomposition temperature(Tid) and thermal degradation activation energy(Ea) increase by 13.1 oC and 5.7 k J·mol-1, respectively, when the MWCNTs content is 0.066 wt%. The storage modulus( E￠) and glass transition temperature(Tg) also increase when MWCNTs is added. MWCNTs can be used as an efficient toughening modifier and processing aid for PVC/ASA blends.4. The graphene oxide was synthesized using expanded graphite via the modified Hummers method and the PVC/ASA/GO nanocomposites were prepared. The plasticizing behavior, dynamic mechanical properties and thermal stability was measured by torque rheometer, dynamic mechanical analyzer and thermal-gravity analyzer, the mechanical properties was also tested. The results show that GO can reduce the plasticizing time and balance torque of the blend during the milling process; The peak value of tanδ curve first increases and the decrease with the increasing GO content, the Tg of blends is all lower than pure PVC/ASA; The blend show the best impact and tensile strength when the GO content is 0.1 wt%, the maximum impact strength is 2.05 times higher than pure PVC/ASA, the tensile is 14.0 % higher than pure PVC/ASA; The blends show the maximum storage modulus when the GO content is 0.15 wt%, which is 13.0 % higher than pure PVC/ASA.