Blending of polypropylene and polystyrene high speed film laminating machine

日期:2021/7/22 8:41:16 / 阅读: / 来源:本站

Blending of polypropylene and polystyrene high speed film laminating machine
Compared with PP, PS has higher hardness, lower shrinkage and better printability. However, PS has poor environmental stress cracking resistance, toughness and solvent resistance. In order to obtain materials with excellent comprehensive properties, PP and PS were modified by blending, trying to get a kind of composite with excellent properties of PP and PS. PP / PS is a typical incompatible system, so the key to prepare PP / PS alloy with excellent properties is to solve the compatibility and interfacial adhesion between PP and PS. High speed film laminating machine www.handern.com
Because the two resins are completely incompatible, the phase separation of the blends is serious and the properties are poor. PP / PS is easy to graft during melt mixing in extruder, and the graft can act as compatibilizer. When the content of PS is 10%, the grafting effect is the best. In miscible blends, due to the interphase adhesion and the decrease of interphase interfacial tension, the aggregation of dispersed phase is prevented and the dispersed phase is stabilized. The interphase adhesion can be obtained through several mechanisms. The most common and effective method is to add block or graft copolymers of two incompatible homopolymers into the two incompatible polymer blends. When the block or graft polymer exists on the two incompatible interfaces, it can act as an emulsifier and reduce the interfacial tension. Sb (styrene butadiene copolymer), SBS (styrene butadiene styrene triblock copolymer), SEBS (styrene hydrogenated butadiene styrene triblock copolymer), SEPs (styrene ethylene propylene styrene block copolymer), pp-g-ps (PP and PE graft copolymer), pe-g-ps (PE and PS graft copolymer), pp-b-ps (PS and isotactic PP block copolymer), pp-g-ps (styrene butadiene styrene triblock copolymer), pp-g-ps (styrene ethylene propylene styrene block copolymer), pp-g-ps (PP and PE graft copolymer), pp-b-ps (PS and isotactic PP block copolymer) Pp-g-avm and PP-g-MAH can be used as compatibilizers of PP / PS. High speed film laminating machine www.handern.com
The PP / PS (mass ratio 19 / 78) blend was prepared by using hydrogenated SIS (styrene isoprene styrene triblock copolymer) as compatibilizer with 3% addition. It has excellent flexibility, high strength, good plasticity, impact resistance and solvent resistance. Using SEPs block copolymer as compatibilizer, the notched impact strength, yield strength, elongation and elastic modulus of the blends are not only related to the ratio of PP / PS, but also related to the amount of SEPs. With the increase of SEPs content, the T of PP phase decreased. When the mass ratio of PP / PS is 25 / 75, the maximum change occurs. SBS also has compatibilizing effect on PP / PS. With the increase of SBS content, the yield strength and elastic modulus decreased, while the yield elongation and impact strength increased. When the mass fraction of SBS, SEBS and SEPs is 2.5%, 5.0% and 10.0% respectively, SEM analysis shows that the size of PS phase decreases with the increase of the content of compatibilizer. The notched impact strength and elongation at break of the blends increase, but the elastic modulus decreases. The compatibilization effect is related to the chemical structure and molecular weight of compatibilizer. The compatibilizing effect of SEPs is better than that of SBS and SEBS. The tensile strength and elongation at break of the blends increase with the increase of compatibilizer content due to its adhesion and compatibility at the interface of the two phases. Compared with other block copolymer compatibilizers, the impact strength of the blends increases without reducing the rigidity of the blends. The impact strength of PS / PP / SEBS (mass ratio 75:25:10) blend is 14kj / m, the hot deformation temperature is 84 ℃, the bending strength is 35MPa, the bending modulus is 1400MPa, and it has excellent resistance to halogenated hydrocarbon, salad oil and other grease, which can be used to prepare refrigerator internals. The impact strength of PP / PS alloy compatibilized by SBS is obviously higher than that of the alloy compatibilized by SBS. There is compatibilizer between the two phases, which reduces the interfacial tension and increases the interfacial adhesion. When the material is subjected to external force, this good interface structure can play the role of stress dispersion, avoid the occurrence of stress concentration in the interface area, so as to improve the impact resistance of the material. The impact strength of PP / PS alloy can be increased from 4.5kj/m to 18.74kj/m by adding a small amount of SBS (2.5%). It can be seen that the addition of SBS has a great contribution to the improvement of the impact properties of the alloy. PP-g-MAH can also be used as compatibilizer of PP / PS. its processing method is simple and easy, and its compatibilization effect is good. High speed film laminating machine www.handern.com
In situ Compatibilization of Po and PS can be achieved by reactive extrusion. In the presence of catalyst AICL and styrene monomer, pp-g-ps can be formed in the extrusion process of PP / PS by single screw extruder. It plays a compatibilizing role in the matrix of the mixture. The successful development of this low-cost self compatibilization technology will greatly reduce the recycling cost of waste PP and PS mixture. After Dow Chemical Company first reported RPS (reactive PS containing oxazoline side group), a series of research literatures on reactive blending of RPS with other modified copolymers (CPE, MPE) have been published at home and abroad in recent years. It has been reported that PP / PS was modified by RPS to prepare high performance alloy. When RPS / MPP is used as compatibilizer of PS / PP Alloy, the side group of RPS and the anhydride group of MPP react in situ to form PP GPS. The polymer can compatibilize PP / PS alloy in situ and form a unique dual "island" composite structure, that is, PP is continuous phase, PS is dispersed phase, and PS dispersed phase contains PP small particles to form composite particles, At this time, the properties of the alloy are the best. High speed film laminating machine www.handern.com

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