Latent reactive polymers

Ladder polymer, synthesis of, 503 Lanthanide catalysts, 288 Lanthanide compounds, 73 Latent-reactive polymers, 455 Laurolactam, 136... 

Homopolymers and copolymers containing carbosiloxane and carbosilane units have been produced that bear latent reactive sites along the chain [184]. Reactive carbosiloxane and unreactive carbosilane homopolymers were first prepared in order to ensure catalyst monomer compatibility and to set end points for copolymer properties. Carbosiloxane homo- and copolymers were synthesized with latent reactivity dispersed throughout the polymer chain in the form of methyl silyl ethers (Scheme 21). It is well known that Si-OMe bonds, although inert during metathesis, can react with atmospheric moisture creating stable Si-O-Si bonds and methanol [185]. 

Recent developments in ADMET polymerization and its use in materials preparation have been presented. Due to the mild nature of the polymerization and the ease of monomer synthesis, ADMET polymers have been incorporated into various materials and functionaUzed hydrocarbon polymers. Modeling industrial polymers has proven successful, and continues to be appUed in order to study polyethylene structure-property relationships. Ethylene copolymers have also been modeled with a wide range of comonomer contents and absolutely no branching. Increased metathesis catalyst activity and functional group tolerance has allowed polymer chemists to incorporate amino acids, peptides, and various chiral materials into metathesis polymers. Sihcon incorporation into hydrocarbon-based polymers has been achieved, and work continues toward the application of latent reactive ADMET polymers in low-temperature resistant coatings. 

Snitable polymers (snitable in this regard means that the polymer exhibits adjnstable rheology, latent reactivity, and controllable pyrolytic degradation) are synthesized according to well-developed procedures from appropriate monomers... 

To aid processability or provide a higher latent reactivity level, the precursor must commonly contain some additional substituents in the polymer backbone. They give rise to eliminated gaseous products during pyrolysis. The pyrolysis requires close monitoring to ensure conversion to correct SiC material, to prevent retention of impurities or creation of undesired pores. 

Recently, more and more studies have started to focus on side chain engineering, and various flexible chains have appeared in conjugated polymers. These side chains can be categorized based on their compositions, namely, alkyl, hybrid, ionic, oligoether, fluoroalkyl, and latently reactive side chains. In this section, we will introduce some representative side chains used in conjugated polymers, and some recent examples in which side chain engineering has been successfully employed to improve device performance will be highlighted. 

Figure 3.11 The use of reactive terminal olefins to realize the concept of latent reactive" unsaturated polymers with chain-end and chain-internal cross-linking [100],...

Our previous results [1] showed that polymer stmcture and latent reactivity are the driving forces behind ceramic yields, while the chemical content is primarily responsible for the evolution of the ceramic composition. The studies determined that polymer-derived ceramic compositions are controlled mainly by the polymer monomeric units. 

Saccharides have a number of attributes that make them very attractive as raw materials for the synthesis of polymers. The confluence in saccharides of different functionalities such as multiple hydroxyl groups and latent reactivity, which is difficult to realize in wholly synthetic materials, is of particular interest to us. The preparation of monomers derived from saccharides and the subsequent polymerization of these materials is one approach that has been extensively pursued as a means to introduce saccharide groups into synthetic polymers (1-9). With a few exceptions (2), most of this previously reported work has involved attaching a polymerizable moiety onto a mono- or disaccharide. The practical synthesis of a new family of monomers derived from carbohydrates ranging from monosaccharides to large oligosaccharides and the use of these monomers to produce a detectable water treatment polymer are described in this paper. 

Today the technique of photolithography is a central element in microfabrication, most notably of microchips for the integrated circuits that control computers, mobile phones, and so many other accoutrements of modern life. The principle is simple enough. A mask with a pattern of holes is the template. It is placed over a silicon wafer coated with a photoresist , or resist for short, in the form of a reactive polymer. The resist is rendered insoluble in a chemical solution only after a reaction provoked by ultraviolet light. Irradiation through the mask then prints a latent image, as in photography, on the wafer surface. The wafer is treated with the solvent (the developer ). 

The principal monomers butadiene, styrene, vinyl acetate, (meth)acrylates and acrylonitrile essenhally determine the material properties of films made from the corresponding dispersions the glass transition temperature, the water absorption capacity, the elasticity, etc. Auxiliary monomers, which are only used in a small proportion, usually <5 %, control important properties such as colloid-chemical stabilization (acrylic acid, methacrylic acid, acrylamide, methacrylamide), crosslinking within the particles (difunctional acrylates, divinylbenzene, etc.) or hydrophilic properties (OH-containing monomers, such as hydroxyacrylates). Reactive monomers which still contain a latently reactive group even after incorporation into the polymer, for example glycidylmethacrylate or N-methylol(meth)acrylamide, can form a network between various particles and polymer molecules after film formation. 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Bisbenzocyclobutenes readily react with molecules which contain sites of reactive unsaturation such as bismaleimides [10,13, 31, 32]. This is in essence, a novel type of Diels-Alder polymerization in which the bis-diene is latently embodied within two benzocyclobutene moieties. The properties of these polymers depends strongly on the mole ratio of the monomers and when it is equimolar, can result in some exceptionally tough high Tg resins [33, 34]. 

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