Block copolymers containing methacrylate segments

Polysiloxanes with terminal hexenyl groups were converted by ozonol-ysis into polysiloxanes with terminal aldehyde functionality. These were used in combination with copper octanoate, triethylamine, pyridine and triphenylphosphine to initiate the polymerization of styrene, methyl methacrylate and styrene/methyl methacrylate mixtures at 70°C. The polymerizations yielded block copolymers containing polysiloxane and vinyl (co)polymer segments. Depending on how the polymerizations terminated, the block copolymers had triblock or multiblock architectures. 

Hyperbranched polymers synthesized by ATRP using mixed monomers , structures that contain combinations of (meth)acrylates with a-haloesters [262], have also been reported. For example, 2-(2-bromopropionyloxy)ethyl methacrylate (BPEM) contains the methacrylate and bromopropionate groups which form tertiary and secondary radicals, respectively. Likewise, the monomer 2-(2-bromoisobutyryloxy)ethyl acrylate (BIEA) contains the secondary acrylate group with a tertiary 2-bromoisobutyrate fragment. With these monomers, highly branched macromolecules were obtained. In a similar way, macroinitiators were used to reduce the proportion of branched units [263]. They may be considered a segmented block copolymers. 

Compatibilisers are intentional additives, incorporated into multi-component, multiphase polymer systems. They are usually block copolymers, whose segments are soluble in different components of the mixture. Compatibilisers can be reactive (if they form bonds with one of the polymers in the mixture) with reactive groups like acrylic or methacrylic, maleic anhydride, or glycidyl methacrylate), or non-reactive. The main classes of compatibilisers are (a) modified PE and polypropylene-styrene containing polymers, (b) macromonomers, (c) silane-modified materials. 

Similar block copolymers have also been prepared by coupling methyl methacrylate macroanions and suitably terminated poly(ethylene oxide)( )and by the initiation of methyl and ethyl methacrylate by alkali metal alkoxides of poly(ethylene oxide)( 3). styrene containing block copolymers have also been produced( ). In the former plus latter techniques the ester containing block segments were subsequently hydrolyzed to methacrylic acid thus making them water soluble. 

The water-soluble amphiphilic copolymers of MPC and -butyl methacrylate (BMA) have been extensively studied for DDS applications. The PBMA units assemble in water as a result of the hydrophobic effect and the copolymers form aggregates that can solubilize hydrophobic bioactive agents in the core PBMA segments. Paclitaxel, a very hydrophobic anticancer drug that is poorly soluble in aqueous medium (<0.3 pg mL ), can be better dissolved at more than 2 mg mL using P(MPC-Z)-BMA) block copolymers. Recently, Ishikawa et aZ. developed an emulsion lotion containing commercially available P(MPC-co-BMA) for the controlled release of water-insoluble diphenhydramine, which is a widely used antihistamine for... 

Radicalized VDC statistical copolymer with Zonyl has been shown to be capable of formation of various block copolymers, which in turn can also be reactive intermediates. This is true with the RBl-200 and RBI-232 products described in Section 4.2, in which the second block contains epoxide groups from glycidyl methacrylate. Another product, called RBI-201, was similar to RBl-200 but contained Zonyl TM segments in the second block (see synthesis procedure in Table 4.3.1). 

Utama et al. [46] recently proposed an alternative strategy for the preparation of nanocapsules using RAET polymerization in an inverse miniemulsion system. In this approach, dispersed aqueous droplets (with RAET-based active stabilizers at their interface) simply acted as templates, and chain extension (with hydrophobic monomers and crosslinkers contained in the surrounding continuous phase) yielded the nanocapsules. More specifically, methyl methacrylate (MMA) [46] or styrene [47], crosslinker (EGDMA or DVB, respectively), and initiator (AIBN) were dissolved in a toluene continuous phase. Water droplets containing sodium chloride as lipophobe were formed in these toluene solutions and stabilized with RAET-synthesized poly[M-2-(hydroxypropyl methacrylamide)]-h/oc -poly(methyl methacrylate) (PHPMA-h-PMMA) or PHPMA-h-PS block copolymers, where the PHPMA segment is hydrophilic. The subsequent polymerization was confined to... 

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