POE elastomer modification of general plastics is mainly studied as a toughening agent to modify rigid general plastics, improve the toughness of rigid general plastics or improve the performance of general polyethylene (PE) by blending. There are few researches on PE/POE system outside China, and more and more researches are reported on POE toughening rigid PP.

1, PE/POE system

In recent years, wood-plastic composites have been widely concerned because of their advantages of low cost, good performance, light weight and small wear on processing equipment. However, after filling wood powder with thermoplastics, the composite becomes brittle, which limits the application and promotion of wood-plastic composite materials. Wood-plastic composites were prepared by filling high density polyethylene (HDPE) with waste wood powder. Metallocene polyethylene (mPE) and POE were used to toughen the composites, and the toughening effect of these two toughening agents was comprehensively evaluated. When the dosage of the two is less than 12 parts, the toughening effect of the two is not much different; However, after the dosage is greater than 12 parts, the impact strength and elongation at break of the composite material toughened with POE increase very rapidly, while the increase rate is relatively gentle when toughened with mPE; The toughening effect of POE is significantly better than mPE. The mechanical and thermal properties of HDPE and POE blends were studied. The thermal analysis results showed that HDPE and POE had certain interaction. When POE content ≥ 5%, the material is super-tough at room temperature. The foaming material prepared by

POE modified PE has good toughness, elasticity and strength, and can be used as adhesive tape. 30 parts of PE containing ion structure and 6.5 parts of azodicarbonamide are added to 100 parts of the mixture composed of 30% POE and 70% Affinity PL 1845, extruded into sheets, radiation crosslinking, foaming at 250¡æ, the resulting 1mm thick foam sheet has good toughness, The bending strength of the transverse and longitudinal directions is 30.2MPa and 24.3MPa, respectively. POE/PE composite material can be made into microporous film, which is used for the isolation layer of capacitors, diapers, sanitary napkins, packaging film isolation layer, etc.

2, PP/POE system

As we all know, as a large variety of general plastics, polypropylene (PP) has the shortcomings of poor low temperature toughness and notch sensitivity, therefore, in order to improve the performance of PP, elastomer toughening modification has been regarded as the most effective way. Although EPDM has a good toughening effect on PP, the price of EPDM is high, the broken glue has certain difficulties, and the fluidity is not ideal. The advent of POE makes it have incomparable advantages over traditional elastomers in the toughening modification of PP. POE toughening PP can not only overcome the shortcomings of EPDM toughening PP, but also give PP higher toughness, high transparency, high performance/price ratio and other characteristics. The study pointed out that compared with EPDM toughening PP, whether it is for ordinary PP, copolymerization PP or high fluidity PP, POE toughening effect is better than EPDM, and the bending modulus and tensile strength are reduced less. The content of octene in POE affects the toughening effect of POE on PP. With the increase of the content of octene in POE, the crystallinity, melting point and density of POE are reduced, the flexibility is increased, and the toughening effect of PP is improved.

Commercialized POE itself is granular, and can be directly added to other materials such as PP for modification. Therefore, POE is more simple than EPDM rubber modifier processing operation, which can greatly reduce the production cost. The PP/POE blending system was studied and compared with the PP/EPDM blending system. The results show that the two blends have similar crystallization behavior and mechanical properties, but the PP/POE blends have lower torque and better processing performance. As an impact modifier of PP, POE has obvious price and performance advantages over EPDM.

The phase structure, toughening mechanism and mechanical properties of PP/POE blend system were studied. The results show that under the same conditions, the amount of POE is less than EPDM, and the brittle and tough transformation can be achieved when the amount of POE is 20 parts. In the PP/POE blending system, POE forms a uniform "sea-island" structure in the continuous phase of PP; POE toughening PP is in line with the silver shear mechanism, which can effectively improve the impact strength of PP at room temperature and low temperature. The toughening effect of POE on isotactic polypropylene was studied. When the POE mass fraction is between 15% and 25%, the impact strength of the blend increases slowly; The impact strength increases rapidly when POE mass fraction continues to increase; The impact strength is maximum when the POE mass fraction is 40%. Morphological and structural analysis shows that the dispersed phase size increases with the increase of POE mass fraction; The synergistic effect of the components of the blend significantly increased the impact strength.

3, general plastic /POE/ inorganic filler system

How to reduce the amount of toughening agent POE to reduce the cost without affecting the toughening effect, which is the hot point and direction of the research and development of general plastic /POE system. The addition of inorganic or organic fillers in the blend can reduce the raw material cost of the product to achieve the purpose of increment, or the performance of the product has been significantly improved, in recent years can be seen in the general plastic /POE blending system to add inorganic fillers reported.

In view of the shortage of ring stiffness of the pipe produced by recovering high density polyethylene (RHDPE), the RHDPE was modified with talc powder and homemade modified POE(MPOE), and the influence of the dosage of talc powder and MPOE on the mechanical properties of the blending system was studied. The results show that when the mass ratio of RHDPE/MPOE/ talc is 50/10/40, the overall mechanical properties of the system are 50/10/40. When the dosage of talc was 40%, the ring stiffness of RHDPE pipe was 54% higher than that of non-modified RHDPE pipe. At the same time, they also studied the mechanical properties of PVC/MPOE/ inorganic filler system. The results showed that when the mass fraction of talc or calcium carbonate in the filler masterbatch was 70%, the comprehensive performance of the ternary composite system was the best. China foreign PP/ elastomer and PP/ inorganic nanoparticle system were studied. The improvement of toughness or rigidity shown by these two systems is at the expense of other properties. Therefore, the toughening of elastomer and the toughening and strengthening of inorganic nanoparticle are combined at the same time. The generation of a PP/ elastomer/inorganic nanoparticle multiphase composite system is gradually becoming a new research hotspot.

High performance PP/POE/ nano kaolin ternary composite material was prepared by alloying technology and filling composite process. The results show that the nano-kaolin and elastomer POE have a synergistic effect on PP toughening, which is not a simple addition of the two independent toughening effects; The optimal dosage of nano-kaolin is 5%. The impact section of PP/POE(20%)/ nano-kaolin (5%) was observed by scanning electron microscope (SEM). It can be seen that the kaolin particles were coated by the matrix and dispersed in the blend matrix with a layered structure, and the interface was firmly bonded.

Study PP/POE/ nano-sio2 composites after the conclusion: melt blending method makes POE and SiO2 uniformly dispersed in the PP matrix, when the ratio of PP/POE/ nano-sio2 100/15/4, the composite has the best comprehensive performance. Although the dispersion of nano-sio2 particles in PP is distributed as a particle aggregate, its secondary particle size is equivalent to and less than the critical particle size, so it plays the role of absorbing energy and hindering crack propagation when it is impacted, thus improving the toughness of the material.

PP/ elastomer/nano CaCO3 composite material was studied and found that the impact strength of the material was good; POE has better toughening effect than HDPE, and the tensile strength of the material decreases with the increase of the content of the elastomer. Transmission electron microscopy (TEM) showed that nano CaCO3 had reached nano dispersion in PP matrix. The results show that nano-cacO3 can improve the defects caused by the decrease of hardness caused by POE, and the tensile strength and bending strength can be improved. The modification effect of activated nano-cacO3 is much better than that of unactivated nano-cacO3, and the best enhancement effect is about 8 parts. The composite material was strengthened and toughened at the same time.

PP/POE system has excellent comprehensive performance, and has been developed a variety of products, especially car bumpers have broad market prospects. It is usually required that the notched impact strength of PP bumper special materials (room temperature) is greater than 500J/m, and the notched impact strength of -40¡æ ≥ 50J/m. Using PP as the base resin, POE as the toughening agent and talc powder as the reinforcing filler, the special material for automobile bumper with the performance meeting the requirements was prepared. The modified PP has ultra-high impact strength, and its notched impact strength is as high as 723J/m, and it has enhanced softness, excellent heat resistance, low temperature resistance and aging resistance. With small bulk polypropylene (PP) as the base material, through blending with CPP, POE, wollastonite and other additives modification, the automobile special material for bumper and door panel is prepared. The test and analysis show that the formula design of PP/CPP/POE/ wollastonite blend system is reasonable, the process route and parameters are correct. When the mass ratio of PP: CPP: POE: wollastonite is 45~ 48:26 ~ 29:19 ~ 22:4 ~6, the blend can fully meet the performance requirements of automobile bumper. When the mass ratio of PP: CPP: POE: wollastonite is 45~ 50:27 ~ 29:3 ~ 6:17 ~20, the blend can fully meet the performance requirements of automotive door panels. It is found that the comprehensive performance of POE modified PP is better than that of traditional toughening agent. Wollastonite also has a certain toughening function, which partly plays the role of glass short fiber.

Thermoplastic vulcanizate (TPV) can be obtained by the method of crosslinking PP and elastomer, TPV has high application value in practical production. POE was grafted with vinyl silane and dispersed in PP, and the blend was crosslinked with hydrolyzed water to obtain TPV; The TPV obtained is easy to be processed into products and has excellent surface properties. The product has high breaking strength and elongation at break, wide range of Shore hardness, very low fog degree, POE without odor, and can be widely used in the automotive field.

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