Polymers polymethacrylates

Kholodovych V, Gubskaya A, Bohrer M et al. (2008) Prediction of biological response for large combinatorial libraris of biodegradable polymers polymethacrylates as a test case. Polymer 49 2435-2439... 

Synthetic polymers can be prepared to contain chirality as is the case for cellulose and other natural polymers. Chirality can be introduced into the monomer before polymerization to yield the chiral polymer. Alternatively polymerization of an achiral monomer in the presence of some chiral catalyst yields the chiral polymer. Polymethacrylates exhibiting chirality due to single-handed helicity have been prepared via polymerization in the presence of a chiral catalyst. These materials are used in liquid chromatography primarily under low-pressure conditions and have shown good resolution for compounds capable of hydrogen-bond formation. 

Research into liquid-crystalline ferrocene sidechain polymers has been conducted by the research groups of Zentel and Deschenaux. One such liquid-crystalline polymer, polymethacrylate (18) and its monomer, showed enantiotropic smectic C and smectic A phases. This polymer also exhibited a weight average molecular weight of 100,000. ... 

VI additives to improve the viscosity index polymethacrylates, polyacrylates, olefin polymers. 

Polymethacrylates are less soluble than hydrocarbon polymers in mineral oils, they thicken less at low temperatures and are more effective at high temperatures. In this respect, it is important to note that the modification of rheoiogical properties is based on interactions between polymer and oil it will therefore be always dependent of the nature of oil. 

Pour-Point Depressants. The pour point of alow viscosity paraffinic oil may be lowered by as much as 30—40°C by adding 1.0% or less of polymethacrylates, polymers formed by Eriedel-Crafts condensation of wax with alkylnaphthalene or phenols, or styrene esters (22). As wax crystallizes out of solution from the Hquid oil as it cools below its normal pour point, the additive molecules appear to adsorb on crystal faces so as to prevent growth of an interlocking wax network which would otherwise immobilize the oil. Pour-point depressants become less effective with nonparaffinic and higher viscosity petroleum oils where high viscosity plays a dominant role in immobilizing the oil in a pour-point test. 

Viscosity (Viscosity-Index) Improvers. Oils of high viscosity index (VI) can be attained by adding a few percent of ahnear polymer similar to those used for pour-point depressants. The most common are polyisobutylenes, polymethacrylates, and polyalkylstyrenes they are used in the molecular weight range of about 10,000 to 100,000 (18). A convenient measure for the viscosity-increasing efficiency of various polymers is the intrinsic viscosity Tj, as given by the function... 

Polymethacrylates. Poly(methyl methacrylate) [9011-14-7] is a thermoplastic. Itis the acryUc resin most used in building products, frequendy as a blend or copolymer with other materials to improve its properties. The monomer is polymerized either by bulk or suspension processes. Eor glazing material, its greatest use, only the bulk process is used. Sheets are prepared either by casting between glass plates or by extmsion of pellets through a sHt die. This second method is less expensive and more commonly used. Peroxide or azo initiators are used for the polymerization (see Methacrylic polymers). 

The most commonly used polymers are cellulose acetate phthalate [9004-38-0] (CAP), poly(vinyl acetate phthalate) [34481-48-6] (PVAP), hydroxypropylmethyl-ceUulosephthalate [71138-97-1] (HPMCP), and polymethacrylates (111) (see Cellulose esters). Acrylate copolymers are also available (112). Eigure 11 shows the dissolution behavior of some commercially available enteric materials. Some manufacturers supply grades designed to dissolve at specific pH values with increments as small as 0.5 pH unit (113). 

This family includes a range of polyacrylates (III), polymethacrylates (IV) and the important fibre-forming polymer, polyacrylonitrile (V). 

The pore size, the pore-size distribution, and the surface area of organic polymeric supports can be controlled easily during production by precipitation processes that take place during the conversion of liquid microdroplets to solid microbeads. For example, polystyrene beads produced without cross-linked agents or diluent are nonporous or contain very small pores. However, by using bigb divinylbenzene (DVB) concentrations and monomer diluents, polymer beads with wide porosities and pore sizes can be produced, depending on the proportion of DVB and monomer diluent. Control of porosity by means of monomer diluent has been extensively studied for polystyrene (3-6) and polymethacrylate (7-10). 

Synthetic organic polymers, which are used as polymeric supports for chromatography, as catalysts, as solid-phase supports for peptide and oligonucleotide synthesis, and for diagnosis, are based mainly on polystyrene, polystyrene-divinylbenzene, polyacrylamide, polymethacrylates, and polyvinyl alcohols. A conventional suspension of polymerization is usually used to produce these organic polymeric supports, especially in large-scale industrial production. 

In the next step, the best candidate from the series 2-oxo-4-(9-phenanthryl)-dihy-dropyrimidine 22 was prepared and isolated in enantiomerically pure form, then attached to a macroporous polymer support. To attach the isolated selector to the amino functionalized macroporous polymethacrylate support, a suitable reactive handle had to be introduced into the dihydropyrimidine. We chose to functionalize the methyl group at the C6 carbon atom by a simple bromination to afford (-)-22. Coupling of this compound to the amino functionalized support then gave the desired chiral stationary phase CSP 12 (Scheme 3-6) containing 0.20 mmol g of the selector. 

Methacrylic acid and its esters are useful vinyl monomers for producing polymethacrylate resins, which are thermosetting polymers. The extruded polymers are characterized by the transparency required for producing glass-like plastics commercially known as Plexiglas ... 

Kolarik, J. Secondary Relaxations in Glassy Polymers Hydrophilic Polymethacrylates and Polyacrylates Vol. 46, pp. 119—161. 

By coelectrolysis of polymethacrylic acid with e-acetaminocaproic acid or cyano-acetic acid the alkylacetamido- or cyanomethyl group can be grafted on to the main chain of the polymer [205]. 

Chain growth polymerization. Important polymers manufactured hy chain growth are polyethylene, polystyrene, polyacrylonitrile, and polymethacrylates. 

Gregor, H. P. Frederick, M. (1957). Titration studies of polyacrylic acid and polymethacrylic acids with alkali metals and quaternary ammonium bases. Journal of Polymer Science, 23, 451-65. 

Michaeli, I. (1960). Ion-binding and the formation of insoluble polymethacrylic salts. Journal of Polymer Science, 48, 291-9. 

We have cited the case of epoxidation with peracids earlier in this book. A cross-linked polymethacrylic acid can, in principle, be treated with a sulphonic acid catalyst and H2O2 to give the peracid, which will allow epoxidation to be carried out in a convenient way, while the polymer can be reused. The key advantage is that the product stream does not contain an acid, which may be harmful in several ways. 

Table I demonstrates that most liquid crystalline polymers lacking a spacer are formed from a flexible polyacrylate backbone. In contrast, the methyl substituent in polymethacrylate backbones both reduce main chain mobility and imposes additional steric barriers to mesophase formation. Therefore, successful liquid crystalline formation of polymethacrylates has been achieved only...

Hydration of polymeric membranes may be influenced by the chemical identity of the polymers. A hydrophilic polymer has a higher potential to hydrate than a hydrophobic one. Sefton and Nishimura [56] studied the diffusive permeability of insulin in polyhydroxyethyl methacrylate (37.1% water), polyhydroxy-ethyl acrylate (51.8% water), polymethacrylic acid (67.5% water), and cupro-phane PT-150 membranes. They found that insulin diffusivity through polyacrylate membrane was directly related to the weight fraction of water in the membrane system under investigation (Fig. 17). 

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