Graft copolymers polystyrene

E Bayer, M Dengler. B Hemmasi. Peptide synthesis on the new polyoxyethylene-polystyrene graft copolymer, synthesis of insulin B21.30. btt J Pept Prot Res 25, 178, 1985. 

The new synthetic approach being adopted for the preparation of the lignin-polystyrene graft copolymer involved three steps. 

A polyethylene glycol-polystyrene graft copolymer palladium catalyst has been used in allylic substitution reactions of allyl acetates with various nucleophiles in aqueous media.58 Another polymer-bound palladium catalyst 40 was developed and used in a Heck coupling of allylic alcohols with hypervalent iodonium salts to afford the substituted allylic alcohols as the sole products under mild conditions with high catalytic efficiency.59 The same polymer-bound palladium catalyst has also been used for Suzuki cross-coupling reactions.60... 

Strength properties of rayon-polystyrene graft copolymers (single fiber tests) (108)... 

Bonding of hydrophobic plastic materials to wood to create new wood-plastic (polystyrene) materials with improved mechanical and physical properties that incorporate the desirable features of each constituent is difficult to achieve. This is due to poor interfacial adhesion between the wood and polystyrene components because of their inherent incompatibility. New, well-defined, tailored cellulose-polystyrene graft copolymers have recently been prepared using anionic polymerization techniques. Preliminary bonding studies showed that these graft copolymers can function effectively as compatibi-lizers or interfacial agents to bond hydrophobic plastic (polystyrene) material to wood, evolving into a new class of composites. 

Preparation of Cellulose-Polystyrene Graft Copolymers. The polystyr-yl mono- and di-carbanions were prepared in THF at -78 °C by using n-butyl lithium and sodium naphthalene as the initiators, respectively. The carban-ions were reacted with dry carbon dioxide. The products were precipitated in methanol, filtered, washed with water and methanol, and dried. Size exclusion chromatography (SEC) established that the molecular weight of the polystyryl monocarboxylate was 6,200 and that of the polystyryl di-carboxylate 10,2000. The mono- and di-carboxylates were reacted with mesylated cellulose acetate in dimethylformamide at 75 °C for 20 h to give the cellulose-polystyrene graft copolymer (GP 1) and crosslinked cellulose-polystyrene graft copolymer (GP 2), respectively. 

Synthesis of Tailor Made Cellulose-Polystyrene Graft Copolymers... 

Using a different approach, Hazer and Kurt [38] achieved the synthesis of polystyrene grafted copolymers with polybutadiene backbones. The method includes the synthesis of a macroperoxide initiator containing polystyrene which further reacts on the double bonds of PBd. 

The reaction scheme for graft copolyelectrolyte synthesis by free radical copolymerization according to the macromonomer technique is shown in Scheme 15. Besides the aspect of how to control the constitution of the graft copolyelectrolyte, suitable characterization techniques for unequivocal proof of the attained copolymer structure will also be elucidated. The synthesis, characterization and properties of the inversely structured poly(acrylic acid)-g-polystyrene graft copolymers it are covered in another article in this volume [178]. 

Fmoc-aminomethyl-3,5-dimethoxyphen-oxy)valeric acid PEG, polyethylene glycol PEG-PS, polyethylene glycol-cross-linked polystyrene graft copolymer PS, copoly-(styrene-1% divinylbenzene) polymeric support , resin SPPS, solid-phase peptide synthesis tBu, tert.-butyl TEA, trifluoro-acetic acid TFE, trifluoroethanol THF, te-trahydrofuran TLC, thin-layer chromatography. Amino acid symbols denote the L-con-figuration. All solvent ratios and percentages are v/v unless stated otherwise. 

The Uozumi group developed unique recyclable amphiphilic resin-supported tri-arylphosphines (PEP) attached to polyethylene glycol-polystyrene graft copolymer (PEG-PS), and found that Pd(PEP) is an active catalyst for allylation in water [40a]. They immobilized a chiral amine on PS-PEG-NH2 resin to give PS-PEG resin-supported chiral P,N-ligand R,S) 106. Asymmetric allylation of diethyl malonate... 

PEP = poly(ethylene glycol)-polystyrene graft copolymer... 

Figure 7.4. Modulus-temperature behavior of nylon 6/polystyrene graft copolymers. —, 50% N 75% N O, Nylon 6 A, polystyrene. (Matzner et al, 1973.)...

Polymethyl methacrylate/polystyrene graft copolymers were made by Graham (8) by reaction of the terminal amino group of NaNH2-initiated polystyrene with the pendant NCO groups of methyl methacrylate/IEM copolymers. 

The polymer carbanion can also be used as an anionic initiator for polymerizing a conventional organic monomer to generate a poly-phosphazene-co-organic polymer (Fig. 3.50). The polystyrene graft copolymer prepared as shown above is actually separated into the individual polystyrene and polyphosphazene phases. This is found by the detection of two separate Tg s at +100 °C and +37 °C. 

Scheme 8. Photoxidation of polybutadiene-polystyrene graft copolymer (HIPS).

Because such polyether spacer polymers are also of interest in other fields of polymer-supported immobilization, the first reports published on the synthesis of polystyrene graft copolymers date back to almost one decade agp [111,112]. In fact, these graft supports have been applied successfidly in f ds where insoluble polymers with homogeneous phase reacticais are advantageous, e.g., for phase-transfer reactions [113-116]. 

Fig. 5. Solid-phase supports made of synthetic resins. Figs 1 and 2 The nucleoside linkages used on the early polystyrene popcorn supports (3,4). Fig. 3. The nucleoside linkage used on a polyamide based resin (5). Fig. 4 The structure of a polyamide/silica gel composite developed for continuous-flow synthesis (8) Fig. 5. The structure of a PEG-polystyrene grafted copolymer, tentacle support (25). The mean mol wt of die PEG side chain is 3000 daltons. Fig 6 The nucleoside linkage used on the recently introduced highly crosslinked polystyrene support (27).

---