Compatibilizers mechanisms

Converting polymers to almost 35,000 plastics includes mechanical mixing/blending one or more polymers with additives, fillers, and/or reinforcement. They do not normally depend on chemical bonds, but do often require special compatibilizers. Mechanical compounding is extensively used (Chapter 5). 

Blend Prodneer Trade Name Compatibilization Mechanism Blend Type... 

The crystallization behavior and kinetics under isothermal conditions of iPP/SBH and HDPE/SBH blends, compatibilized with PP-g-SBH and PE-g-SBH copolymers, respectively, have been investigated (71). It has been established that the LCP dispersed phase in the blends plays a nucleation role for the polyolefin matrix crystallization. This effect is more pronounced in the polypropylene matrix than in the polyethylene matrix, due to the lower crystallization rate of the former. The addition of PP-g-SBH copolymers (2.5-10 wt%) to 90/10 and 80/20 iPP/SBH blends provokes a drastic increase of the overall crystallization rate of the iPP matrix and of the degree of crystallinity. Table 17.4 collects the isothermal crystallization parameters for uncompatibilized and compatibilized iPP/SBH blends (71). On the contrary, the addition of PE-g-SBH copolymers (COP or COP 120) (2.5-8 wt%) to 80/20 HDPE/SBH blends almost does not change or only slightly decreases the PE overall crystallization rate (71). This is due to some difference in the compatibilization mechanism and efficiency of both types of graft copolymers (PP-g-SBH and PE-g-SBH). The two polyolefin-g-SBH copolymers migrate to blend interfaces and... 

PA6AJHMWPE using HDPE-g-MAH as compatibilizer Mechanical properties HDPE-g-MA improved mechanical properties of blends Zhao 2005... 

Blend Producer Trade name Compatibilization mechanism Blend type... 

Yuan et al. [120] has reported the research on PLA/PBAT blend foam. Maleic anhydride is used to enhance compatibility between PLA and PBAT. The compatibilization mechanism of maleic anhydride (MAH) is that MAH enhances intermolecular force by forming hydrogen bond between grafted MAH and polymer backbone. Grafting MAH onto PLA and PBAT is performed by reactive extrusion, which can improve the interfacial adhesion between PBAT and PLA matrix. In order to increase the maleicing reaction activity, a free radical initiator, 2, 5-dimethyl-2, 5-di-(/er/-butylperoxy) hexane (LlOl), can be used. 

Both points can be achieved by adding small amounts of a third component to the blend to act as a bonding agent between the two incompatible phases. Depending on the chemical structure of both compatibilizers and components of the blends, the compatibilization mechanism is different. When the macromolecular compound is a copolymer having monomer units which are identical to, or at least compatible with, each phase, there is physical bonding. The copolymer is miscible with the two phases, creating a bond between the two completely immiscible phases. 

Key Words Comonomer, Organic clay, Nanocomposite, Compatibilizer, Mechanical property. 

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