| Polyvinyl chloride(PVC)is one of the world's five general-purpose plastics,and is widely used in various fields.PVC film has an important application direction of polyvinyl chloride.Due to its low price and mature technology,it is used in the field of membrane materials and occupies a considerable part of the market.However,due to the defects of the PVC resin itself,the PVC film also has some defects such as poor toughness,insufficient strength,poor heat resistance,and aging,which limits the further expansion of its application range.Therefore,the polyvinyl chloride film must be modified to improve the overall performance in order to meet the requirements of people's use,and further expand the application field of the polyvinyl chloride film.In this paper,a kind of PVC film with a semi-interpenetrating network structure is prepared with glycidyl methacrylate(GMA)polymerizing and cross-linking in a PVC resin matrix and interpenetrating with PVC macromolecules.The optimum process condition for preparing semi-IPN PVC/PGMA film is as follows,GMA is 1phr,polymerization time is 1h,and crosslinking time is 0.75h.At this time,the semi-interpenetrating film has the best tensile properties,the tensile strength is 16.29MPa,and the elongation at break is 473.87%.Compared with the unmodified PVC film,the tensile strength of the semi-IPN PVC/PGMA film increases by 8.31%,and the elongation at break is increased by 8.45%;The heat resistance increases,the residual weight at 700°C increases from 2.83%to 7.16%,and the maximum weight loss rate decreases from 1.29%·°C-1 to 1.11%·°C-1;The anti-aging performance is improved,and the film performance aging rate decreases from 10.51%to8.780%after 96h heat aging test;Dynamic mechanical properties are also improved,and both storage modulus and loss modulus increase at a low temperature.Then,the modification of the semi-IPN PVC/PGMA film by organic copolymerization modification and inorganic filler modification is carried out respectively,and the effects of the two modification methods on the properties of semi-interpenetrating PVC film are discussed.The copolymer PGMA-co-PS is prepared by emulsion copolymerization method using glycidyl methacrylate(GMA)and styrene(St)as reactive monomers.And the effects of the ratio of GMA to St on the tensile of the PVC film are discussed.It is determined that the semi-IPN PVC/PGMA film modified by the copolymer PGMA-co-PS of which the ratio of GMA:St=2:1 has the best tensile performance,and the tensile strength and the elongation at break are 16.26MPa and 467.61%,respectively.It is found that the semi-IPN PVC/PGMA-co-PS film is not much different in all aspects from the semi-IPN PVC/PGMA film,but compared with the unmodified PVC film,the performance of semi-IPN PVC/PGMA-co-PS film is improved,the tensile strength increases by 8.11%,the elongation at break increases by 7.02%;The thermal stability at low temperature increases,and the residual weight at 700°C increases from 2.83%to 3.75%;The aging resistance is slightly improved,and the aging rate after 96 hours decreases from 10.51%to 10.15%;The storage modulus and loss modulus under low temperature conditions are improved,and the dynamic mechanical properties are better.Then,the semi-IPN PVC/PGMA film is modified by adding montmorillonite.The organic montmorillonite(OMMT)is prepared by solution intercalation method.The effects of the amount and organic modification of montmorillonite on the tensile properties of semi-IPN PVC/PGMA film are discussed.It is determined that the optimum amount of OMMT on the tensile properties of semi-IPN PVC/PGMA/OMMT is 1.2phr.The tensile strength of the film is 20.91MPa,the elongation at break is 490.42%,which is 39.03%and 12.24%higher than those of the unmodified PVC film,respectively;The thermal performance is significantly improved,the residual weight at 700°C increases from 2.83%to 7.19%,and the maximum weight loss rate decreases from 1.29%·°C-1 to 1.04%·°C-1;The aging performance is greatly improved,and the aging rate of tensile properties decreases from 10.51%to 4.690%after the heat aging test of the film for 96h;The dynamic mechanical properties are also significantly improved,and the storage modulus and loss modulus at low temperatures significantly increase.Finally,the tensile properties,thermal properties,anti-aging properties and dynamic mechanical properties of four films,(PVC film,semi-IPN PVC/PGMA film,semi-IPN PVC/PGMA-co-PS film,and semi-IPN PVC/PGMA/OMMT film),are analyzed and compared in this paper,respectively.It is found that the properties of semi-IPN PVC/PGMA film and semi-IPN PVC/PGMA-co-PS film are improved,and the effect of modification is basically the same.When the OMMT is added in the semi-IPN PVC/PGMA film,the tensile properties,thermal properties,anti-aging properties and dynamic mechanical properties of the prepared nano-composite semi-IPN PVC/PGMA/OMMT film are the best of the four films. |
PDF Full Text Request