Reactive compatibilisation

A typical example of reactive functionalisation is a method for improving the compatibility of polyamide-12 (PA-12) and SAN as described by Yukioka and co-workers. It is known that the mixture of PA-12 and SAN polymers is a typical example of an immiscible polymer system. Therefore, this difficulty could be solved by the addition of PS-co-MA, because the anhydride group of this polymer could react with the terminal amino group of PA. Consequently, the melting point of the functionalised PA significantly decreased (about 25%), which resulted in better miscibility of the SAN polymer [68]. 

A similar method was used for improving the reactivity of polyamide-6 (PA-6) in the experimental work of Dedecker and co-workers [69]. They also demonstrated, using optimum curves, that the PA-co-MA content had an effect on the equilibrium interfacial layer thickness. The maximum value of the equilibrium interfacial layer thickness ( 50 nm) was found when the PA-co-MA contained 15% MA. 

Pruthtikul and co-workers demonstrated the in situ reactive functionalisation of PP in a twin-screw extruder. Dicumyl peroxide was used as the precursor during functionalisation. It was found that the sample acid number significantly changed as a function of the precursor/MA ratio. Their results showed that PP-g-MA, which has a high acid number, had a greater effect on improving the compatibility of the PP/ 

PA-6 polymer blend. Basically, both the tensile strength and impact strength of the composites were better in the presence of PP-g-MA, which had a high acid number, than in samples without the addition of the compatibiliser. Based on the surface analysis, better adhesion was also demonstrated using scanning electron microscopy (SEM) micrographs [70]. 

It was demonstrated by Chen and co-workers that the EPDM/PP blend was immiscible below the upper critical solution temperature and above the lower critical solution temperature, i.e., the investigated EPDM/PP blend was only miscible between the aforementioned critical solution temperatures (lower and upper) [74]. 

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Single- and twin-screw extruders with customised screw profiles are used to produce low density PETP-PP foams in the presence of reactive compatibiliser and coagents. Low density PETP foam is also produced from... 

J. Pospfsil, I. Forteln, D. Micheilkovei, Z. Kruli , and M. Slouf, Mechanism of reactive compatibilisation of a blend of recycled LDPE/HIPS using an EPDM/SB/aromatic diamine co-additive system, Polym. Degrad. Stab., 90(2) 244-249, November 2005. 

The problem of physical blends is not only the formation of a stable morphology. A more important problem for the users of such materials is the changing and most often the lowering of material properties. Table 9 [13] lists the effect of the reactive compatibilisation of polypropylene PA-6 blends of different compositions ... 

The reactive compatibilisation between PP and PA-6 retain the material properties of the starting material PP without lowering the properties with increasing PA-6 content. Sometimes a slight improvement could be observed. 

The chemical structure of polyamides and polyester involves only few chances for a reactive compatibilisation during melt processing with short residence times... 

A highlight of the reactive compatibilisation of extremely incompatible polymers is the chemical bonding between the anti-adhesive PTFE and the polar polyamides. It had been assumed for a long time that a chemical bonding between PTFE and polyamide is impossible because there was no appropriate reaction mechanism. PTFE is a highly crystalline polymer which could only be processed by using special equipment. The utilisation in tribological systems is a well-known... 

PP-LDPE with poly(propylene-g-maleic anhydride) and poly(ethylene-co-vinyl alcohol) as in situ reactive compatibilisers (117),... 

Thomas S and Groeninckx G (1999) Reactive compatibilisation of heterogeneous ethylene propylene rubber (EPM)/nylon 6 blends by the addition of compatibiliser precursor EPM-g-MA, Polymer 40 5799-5819. 

H. Cartier and G.H. Hu, Compatibilisation of polypropylene and poly-(butylene terephthalate) blends by reactive extrusion effects of the molecular structure of a reactive compatibiliser, J. Mater. Sci., 35(8) 1985-1996, April 2000. 

Jose, S. Thomas, S. Bijn, P.K. Koshy, P. and Karger-Kocsis, J., Thermal degradation and crystaUisation stndies of reactively compatibilised polymer blends, Polym. Degrad. StabiL, 93 (6), 1176-1187 (2008). 

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