Compatibilizers provide better performance of polymer blends

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Polymer blends are expected to grow well in the future as no new polymers are being developed. Polymer blends are used when two different polymers that may not be compatible with each other are required to obtain a balance of properties. For instance, Polyolefins are low cost polymers but do not have adequate barrier properties. They are often blended with Polyamides to enhance the barrier properties.

Compatibilizers are those products that allow blending of two immiscible polymers creating a homogeneous mixture. A compatibilzer works like a surfactant, lowering the interfacial tension between two incompatible polymers, thus allowing them to mix. The blends may continue to have two different phases but behave as if they are miscible. The compatibilizer usually has two parts so that each part can interact with the respective polymer in the blend.

There are essentially two type of compatibilizers :

		Reactive
		Non reactive

Reactive compatibilizers develop covalent bonds while non-reactive compatiblizers are typically miscible with one of the polymers from the blend. A compounder should select the compatibilizer that matches the polymers in the blend. Reactive compatibilizers require a reactive counter group while non-reactive compatibilizers should have good miscibility as well as good viscosity match. Some of the common compatibilizers are:

		Copolymers of Ethylene with either EthyleneAcrylic Acid, ButylAcrylic Acid or MethylAcrylic Acid
		Ethylene-butylacrylate-glicidyl methacrylate
		Maleic Anhydride grafted Polyolefins or SBS Copolymers
		Copolymers of PMMA or PS with PP

From the above compatibilizers, copolymers are non-reactive while Maleic Anhydride grafted and Ethylene-butylacrylate-glicidyl methacrylate are reactive compatibilizers.

Crompton, Dexco, Dow, Dupont and Kraton are the major players in the business of compatibilizers. It is estimated that the global market of compatibilizers would grow more than 5% from the level of 15 KT to about 18KT by 2005. All compounders can take the advantage of these compatibilizers to enhance the value of their compounds.