Studies On The Synthesis Of Asa And Its Modification For PVC

The structure of Acrylate-Styrene-Acrylonitrile (ASA) is similar to ABS.The ASA has excellent weatherability,since the polyacrylate rubber with saturated structure which is unlike the polybutadiene rubber of ABS.ASA was first realized industrialization by BASF about40yeas ago.Since the main production technology of ASA was mastered by some foreign large enterprise and there is no company could produce the ASA in our country, the research work is desiderate to development.In this paper,our work was focused on the preparation of ASA resin by multi-micosuspension polymerization;he preparation of ASA core-shell copolymer,and its modification for PVC.The main research works and conclusions are as follows:1.A series of Acrylate-Styrene-Acrylonitrile (ASA) core-shell copolymer were synthesized by emulsion polymerization. The results indicate that the size of the PBA particles synthesized with SDS is much smaller,and the size distribution is narrow;The size of the PBA particles become smaller with the amount of KPS or the polymerization temperature increasing;The grafting degree of the ASA latexes synthesized with SDS and OP-10in the two stages separately is high,and the Core-Shell structure is fairly well.The grafting effect of the ASA synthesized with redox system is much better than KPS. For obtained ASA latexes,the pre-swelling addition of the second-stage monomers to the core latex resulted in a fairly real core-shell structure with transition layer. And it’s two glass-transition temperatures were much closer to each other.2. A series of Acrylate-Styrene-Acrylonitrile (ASA) Core-Shell structure copolymer were synthesized in a two staged emulsion polymerization,and they were used to modify PVC. The results indicate that the melting time is becoming shorter,while the counter balance torque and Maximum torque are increasing as the ASA content increases. The Notched Impact Strength is increasing significantly after the ASA content reaches6phr. In addition, the brittle and ductile features for blends in brittle-ductile transition regions were proved by SEM observation.The melting time gets shorter,while there is a small upward trend for the torque and the Notched Impact Strength of the PVC blends with the increasing of core phase content in ASA. With the increasing of AN in the shell phase of ASA,the melting time does not change sharply,while the torque increases gradually.And the Notched Impact Strength decreases when AN content reaches40%.Influences of Acrylate-Styrene-Acrylonitrile (ASA) core-shell copolymer (synthesized by emulsion polymerization in the laboratory),impact ACR and CPE on the Plastify and Impact Properties of Rigid PVC were studied. The results indicate that with the same using amount of modifiers, the ACR/PVC blends exhibit the characteristics such as shorter melting time,bigger torsional moment and Notched Impact Strength and higher requirement to the processing equipment;The characteristics of ASA/PVC blends are better than CPE/PVC blends and inferior than ACR/PVC blends,and the torsional moment is smaller than ACR/PVC,which has lower requirement to the processing equipment. ASA has a good application prospect.3. A series of Acrylate-Styrene-Acrylonitrile(ASA) resin were synthesized by multi-micosuspension polymerization. The effects on the properties of PBA and ASA resin were investigated. It is found that the Notched Impact Strength of the ASA resin synthesized by multi-micosuspension polymerization is higher than that synthesized by emulsion polymerization and suspension polymerization and which rubber particles are distributed in double peaks;When the mixing proportion of particles with150nm to particles with900nm was30/70, the Notched Impact Strength of ASA resin can reach the maximum value; the Notched Impact Strength increases sharply when rubber phase content is beyond20%;The Notched Impact Strength of ASA resin reaches the maximum value when the amount of EGDMA、ALMA、TDDM are0.43%、0.4%and1%respectively;The Tensile Strength decreases slightly,and the Elongation at Break increases significantly with the amount of rubber phase increasing.