| Polyvinyl chloride (PVC) due to its widely resin powder sources, low production cost price, at the same time the product has a series of excellent properties, which is commonly used for agricultural film, food packaging, biological medicine and other fields. In order to increase resins toughness and flexibility of product, we need to add a large amount of plasticizer in PVC. But in use process, plasticizer will easily migrates from PVC into the surrounding environment, which can change the performance of PVC as well as possible deleterious effect when the plasticizer intrude into human tissue. With the enhancement of people's health and environmental awareness, calling for prohibiting using harmful plasticizer become more and more intense, so the problems of plasticizer migration should be solved. In this paper, using PVC as the matrix, different composites material was produced by microlayer extrusion technology, research of microlayer extrusion technology on suppression plasticizer migration from PVC and its composite was taken. The main content and research results were as follows:(1) The flow channel of lamination unit was simulated by use Moldex3D. The results show that:Melt can uniform flow in the lamination unit because of it reverse curve design, the uniformity of product layer and product quality was improved. It conducive to the uniform dispersion and controlled orientation of fiber, because there is a strong and continuous shear in the reverse runner.(2) Flexible PVC with 1layer,91ayers,81layers,7291ayers were prepared by microlayer extrusion technology and the influences of the technology on plasticizer migration were investigated. It shows that the distribution of PVC molecule chains became more structured and compact along the direction of extrusion, because melting was continuous sheared in the lamination unit. While the orderly arrangement of the molecular chains have a significant effect on suppression plasticizer DOTP transfer to other substances, and the effect was enhanced with the number of microlayers increasing. When using six lamination units, the plasticizer DOTP volatility stability, solvent extraction stability, exudation stability was increased by 64.37%,41.38% and 64.37%.(3) Adding proper amount of nano-CaCO3 into PVC not only can reduce the cost, also can inhibit the migration of plasticizer DOTP. In this paper, PVC/CaCO3 composites was prepared by microlayer extrusion technology. SEM test show that nano-CaCO3 can uniformly dispersed in PVC. When using six multilayer units and the contents of nano-CaCO3 was 9, plasticizer DOTP volatility stability and exudation stability were increased by 76.59% and 89.05%.(4) When organic montmorillonite stripping or controlled orientation distribution in the matrix, it can forming a large number of lamellar structure and extension diffusion path of plasticizer DOTP, which can obviously improve the ability of sample suppression plasticizer migration. In this paper, PVC/OMMT composites was prepared by microlayer extrusion technology. When using six lamination unit and the contents of OMMT was 9, plasticizer DOTP volatility stability, solvent extraction stability, exudation stability were increased by 72.79%,65.75% and 83.33%.(5)Considering the advantages of multilayer extrusion technology in the processing and combining with the blow molding technology, we prepared PVC greenhouse film. Compared to the direct blow molding specimen, the laminated molding specimen has better mechanical properties and more effectively in inhibiting the plasticizer DOTP migration. |
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