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Compatibilization with block copolymers

Also the interfacial layer between the homopolymers differs in A/B - - A-block-B blends from that in A/B - - A-block-B blends. In blends compatibilized with block copolymers having the corresponding blocks miscible with the blend components, they are supposed to be molecularly dispersed to a high degree at the A/B interface (Figs. 9,3). In A/B/A-block-B blends, block copolymers with short A blocks are localized at the A/B interface as well, but they do not lose their ordered supermolecular structure (Fig. 10). Block copolymers having long A blocks are... [Pg.6265]

SCFT today is one of the most commonly used tools in polymer science. SCFT is based on de Gennes-Edwards description of a polymer molecule as a flexible Gaussian chain combined with the Flory-Huggins "local" treatment of intermolecular interactions. Applications of SCFT include thermodynamics of block copolymers (Bates and Fredrickson, 1999 Matsen and Bates, 1996), adsorption of polymer chains on solid surfaces (Scheutjens and Fleer, 1979,1980), and calculation of interfacial tension in binary polymer blends compatibilized by block copolymers (Lyatskaya et al., 1996), among others. [Pg.141]

As shown by examples listed in Table 5.33, PA/PO blends have been compatibilized through block copolymer formation between PA amine end-groups and terminal carboxylic acid groups of polyolefins. PA blends with oxidized PE fall into this category since carboxylic acid groups are located at PE chain ends [see El darov et al, 1996]. [Pg.383]

PA/PS blends have been compatibilized through block copolymer formation between amine-terminated PA and anhydride-terminated PS. Anhydride end-groups were introduced into PS through reaction of either anion-terminated PS or hydroxy-terminated PS with trimeUitic anhydride chloride. Park et al. [1992] blended 80 parts PA-6 with 10-16 parts PS and 4-10 parts anhydride-terminated PS in an internal mixer at 240°C. The blends were characterized by torque rheometry, SEM, selective solvent extraction, DSC, morphological stability to annealing, and lap shear adhesion. The effect... [Pg.384]

There are two mechanisms that may invalidate the above prediction (1) In spite of the best efforts of researchers and technologist, the added copolymer may prefer to form micelles inside one of the polymeric phases than to migrate to the interphase. This has been frequently observed in blends with block copolymers, e.g., for blends of PS with PE, compatibilized by addition of a hydrogenated styrene-butadiene block copolymer, SEES [Utracki and Sammut, 1988, 1990]. (2) Depending on the blend composition, the addition of compatibilizer may affect the total free volume of the system. These changes are difficult to predict. An increase of the free volume (evidenced by reduction of melt density) is expected to result in increased fluidity of the system. [Pg.516]

PA/PC blends have also been compatibilized by block copolymer formation through reactiffli of PA amine end-groups with PC anhydride end-groups (Hathaway and Pyles 1988, 1989). PC phenolic end-groups were anhydride-functionalized by reaction with trimellitic anhydride acid chloride. Extruded blends of PA-6 and PC were characterized by selective solvent extraction and mechanical properties of test parts. An amorphous polyamide could also be compatibilized with PC using this strategy. [Pg.544]

PEST-PPE blends have been compatibilized through block copolymer formation between carboxylic acid end-groups on polyesters, such as PET, and epoxy-terminated PPE (Erown and Lowry 1992a). PPE was functionalized in solution with a variety of chloro-epoxy triazine derivatives in the presence of a base to provide a reactive epoxy triazine-capped PPE (Erown and Lowry 1992b Yates et al. 1992). Melt functionalization of PPE was also possible (Erown et al. 2009). Representative chloro-epoxy triazine capping agents included... [Pg.601]

An important application of block copolymers is as compatibilizers of otherwise immiscible homopolymers. There are a number of useful reviews of work in this area (179-182). The morphology of blends of polymers with block copolymer and theories for this have been reviewed (1). The influence of added homopolymer... [Pg.750]

Numerous reports of comparable levels of success in correlating adhesion performance with the Scatchard-Hildebrand solubility parameters can be found in the literature [116,120-127], but failures of this approach have also been documented [128-132J. Particularly revealing are cases in which failure was attributed to the inability of the Scatchard-Hildebrand solubility parameter to adequately account for donor-acceptor (acid-base) interactions [130,132]. Useful reviews of the use of solubility parameters for choosing block copolymer compatibilizers have been prepared by Ohm [133] and by Gaylord [134]. General reviews of the use of solubility parameters in polymer science have been given by Barton [135], Van Krevelen [114], and Hansen [136]. [Pg.54]

The applicability of Noolandi and Hong s theory of compatibilization of immiscible blends using block copolymers has been extended to the reactive compatibilization technique by Thomas and coworkers [75,76]. According to Noolandi and Hong [77], the interfacial tension is expected to decrease linearly with the addition... [Pg.679]

Polyarylate (PAR)-b-PSt and PAR-b-PMMA for compatibiiizers are described 135,39,40). The addition of PAR-b-PSt (1-10 parts) to 100 parts of a blend of PAR-PSt (7w-3w) resulted in improvement of the tensile and flexural modulus (Fig. 4), and PSt dispersed particles were diminished from 1-5 microns to an order that is undetectable by SEM, indicating the excellent, compatibilizing effect of the block copolymer. The alloy thus formed exert the characteristic of PAR, an engineering plastic, as well as easy processability of PSt. Addition of PAR-b-PMMA (3 or 8 parts) to 100 parts of a blend of PAR-polyvinylidenefluoride (PVDF) (7w-3w) resulted in improved microdispersed state of PVDF due to compatibility of PMMA with PVDF, while segregation of PVDF onto the surface was controlled. [Pg.761]

Mokrini, A., Huneault, M. A. and Gerard, P. 2006. Partially fluorinated proton exchange membranes based on PVDF-SEBS blends compatibilized with methylmethacrylate block copolymers. Journal of Membrane Science 283 74—83. [Pg.184]

These polymers show lower water uptake than the analogous sulfonated poly(arylene ether sulfone) materials, possibly suggesting some interaction between the aromatic nitrile and sulfonic acid. The phosphine oxide functional moiety could also be used as a compatibilizer with other materials. Sulfonated poly(arylene ether phosphine oxide sulfone) terpoly-mers have been prepared both with sulfonated triphenyl phosphine oxide and with triphenyl phosphine oxide with 3,3 -disulfonate-4,4 —dichlorodiphenyl sulfone as the sulfonic acid bearing monomer. Block copolymers containing phosphine oxide appear to avoid the ether—ether interchange that results when non—phosphine oxide blocks are utilized, and this is being further pursued. ... [Pg.358]

Short block copolymers with well defined number of units in the blocks could be applied as selective absorbents, compatibilizers for polymer blends, components for polymeric membranes, etc. [Pg.132]

Chemically unlike polymers are incompatible, and it sometimes happens that the reaction medium is heterogeneous at the beginning. However, once some block copolymer is formed it acts as a "compatibilizer" and the reaction medium gradually becomes homogeneous. Many examples of such reactions could be quoted. A recent one is the hydrosilylation reaction carried out between a polystyrene fitted at a chain end with vinylsilane groups, and an a,u-dihydrogenopolydimethylsiloxane. This process is carried out at high concentration and it yields polystyrene-polydimethylsiloxane-polystyrene block copolymers. 2... [Pg.66]


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See also in sourсe #XX -- [ Pg.11 , Pg.20 ]




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