Copolymer block graft

A combination of TEMPO living free radical (LFRP) and anionic polymerization was used for the synthesis of block-graft, block-brush, and graft-block-graft copolymers of styrene and isoprene [201]. The block-graft copolymers were synthesized by preparing a PS-fo-poly(styrene-co-p-chloromethylstyrene) by LFRP [Scheme 110 (1)], and the subsequent re-... 

ATRP and grafting from methods led to the synthesis of poly(styrene-g-tert-butyl acrylate)-fr-poly(ethylene-co-butylene)-fr-poly(styrene-g-ferf-butyl acrylate) block-graft copolymer [203]. ATRP initiating sites were produced along the PS blocks by chloromethylation as shown in Scheme 112. These sites then served to polymerize the ferf-butyl acrylate. The poly(ferf-butyl acrylate) grafts were hydrolyzed to result in the corresponding poly(acrylic... 

Riess G, Periard J, Banderet A Emulsifying Effect of Block Graft Copolymers - Oil in Oil Emulsions In G. E. Molau (ed) Colloidal and Morphological Behaviour of Block and Graft Copolymers (Proceedings of an American Chemical Society Symposium held at Chicago, Illinois, Sep. 13, 1970)... 

Usually the Zigler-Natta co-ordination initiator system is used to graft oc-olefins onto other polymers to give stereo block/graft copolymers, which contain isotactic/atactic sequences. In the Zigler-Natta co-ordination catalyst [69] system, the diethyl aluminium hydride reacts with pendant groups to form macromolecular trialkyl aluminium. The residual initiator is freed by extraction methods. 

Ceresa, R. 1. Block graft copolymers. Chap. 5. London Butterworth 1962. 

Block—graft copolymers, having a PS—PB diblock as a backbone and PS, PI, PB and PS-b-PI branches, were prepared by anionic polymerization and hydro-silylation reactions.156 The diblock copolymer backbone was prepared by sequential addition of styrene and butadiene. The polymerization of butadiene took place in the presence of dipiperidinoethane, resulting in high 1,2-content. The backbone was then subjected to hydrosilylation in order to incorporate the desired amount of SiCl groups on the PB block. These groups were then used as branching sites, where PSLi, PILi,... 

Se et al. presented the synthesis of poly[(VS- -I)-b-S] block—graft copolymers.157 The backbone, a diblock copolymer of 4-(vinyldimethylsilyl)styrene (VS) and styrene, was prepared first by anionic polymerization. The VS monomer was polymerized selectively through the styryl double bond at low... 

It Is apparent the crystalline cross-links In the block-graft copolymer are as effective as the chemical cross-links In rubber. 

Isobutylene was copolymerized with methylbenzenes by cationic methods to give products containing 1-2% of the comonomer. Attachment of polyplvalolactone grafts was accomplished using the same chemistry as that for Isoprene block-graft copolymers. 

SCHEME 13.12 Photoinduced synthesis of block-graft copolymers using polymeric hydrogen donor and benzophenone. 

Block-graft copolymers are copolymers having one linear block, whereas the other block is a graft copolymer (Scheme 19). 

Using anionic polymerization techniques poly[styrene-b-(4-vinyl phenyl-dimethylsiloxane-g-isoprene)), P[S-fr-(VS-,g-I)] block-graft copolymer was prepared [66,67] according to the following reaction sequence (Scheme 20). 

Block-graft copolymers were also prepared by the grafting from method [67]. The block copolymers P(S-fe-VS) were reacted with n-BuLi in THF at -30 °C for 1 h leading to metallation of the vinyl groups of the V segments. Then D3 was added for the formation of the P[S-fc-(VS-g-DMS)] block-graft copolymer. The molecular characterization revealed that 170 and 325 PDMS branches were incorporated into the backbone for the two samples that were prepared. 

The synthesis of the following block-graft copolymer poly[styrene-fe-(hydrox-ystyrene-g-ethylene oxide)-b-styrene] or P[S-fe-(HS-g-EO)-fe-PS] was reported in the literature [67] according to the Scheme 29. 

PS/PVC graft copolymer A block-graft copolymer was prepared by grafting a di-block copolymer of styrene and butadiene, with cyclohexyl methacrylate monomers. PS/PVC blends comprising small amount of the block-graft copolymer showed excellent behavior. The copolymer had strong effect on the blends morphology. Braun et al., 1994... 

Block-graft copolymers synthesized by covalent conjugation of Pluronic and branched PEI were used as materials for preparation of polyplexes. Such polyplexes usually contain three components (i) DNA (ii) Pluronic-PEI conjugate and (iii) free Pluronic (Fig. 7). The formulations were prepared with both plasmid DNA and oligonucleotides (ODN), resulting in stable polyplex dispersion with the particle size in the ranges of 100—200 nm. These polyplexes were used successfully for delivery of plasmid DNA and antisense ODN in vitro... 

There are a number of polymeric compatibilisers, e.g., block/graft copolymers like tri-block copolymers of SBS used mostly in styrenic blend compatibilisation, and functionalised polymers with certain functional groups (epoxidised or maleated), which can act like a surfactant . 

Cai, Y., Gardner, D., Caneba, G.T. Surface properties of silicone-containing block-graft copolymer/polystyrene systems. J. Adhes. Sci. Technol. 13, 1017-1027 (1999)... 

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