Poly , elastomeric networks

The study of acid-base interaction is an important branch of interfacial science. These interactions are widely exploited in several practical applications such as adhesion and adsorption processes. Most of the current studies in this area are based on calorimetric studies or wetting measurements or peel test measurements. While these studies have been instrumental in the understanding of these interfacial interactions, to a certain extent the interpretation of the results of these studies has been largely empirical. The recent advances in the theory and experiments of contact mechanics could be potentially employed to better understand and measure the molecular level acid-base interactions. One of the following two experimental procedures could be utilized (1) Polymers with different levels of acidic and basic chemical constitution can be coated on to elastomeric caps, as described in Section 4.2.1, and the adhesion between these layers can be measured using the JKR technique and Eqs. 11 or 30 as appropriate. For example, poly(p-amino styrene) and poly(p-hydroxy carbonyl styrene) can be coated on to PDMS-ox, and be used as acidic and basic surfaces, respectively, to study the acid-base interactions. (2) Another approach is to graft acidic or basic macromers onto a weakly crosslinked polyisoprene or polybutadiene elastomeric networks, and use these elastomeric networks in the JKR studies as described in Section 4.2.1. 

Elastomeric networks with junction functionalities ranging from 4 to 70 were prepared by endlinking a,u)-divinyl poly(dimethylsiloxane) chains having number average molecular weights ranging from 8,800 to 55,300 with polyfunctional junctions provided by linear and branched poly(methylhydrogensiloxanes). 

Elastomeric Poly(dimethylsiloxane) Networks with Numerous Short-Chain Segments... 

Hou, Q. P., Grijpma, D. W. Feijen, J. (2009) Creep-resistant elastomeric networks prepared by photocrosslinking fumaric acid monoethyl ester-functionalized poly(trimethylene carbonate) o]igomeis. Acta Biomaterialia, 5, 1543-1551. Ifkovits, J. L. Burdick, J. A. (2007) Review Photopolymerizable and degradable biomaterials for tissue engineering apphcations. Tissue Engineering, 13, 2369-2385. 

Sharaf, M. A. Mark, J. E. Al-Ghazal, A. A.-R., Elastomeric Properties of Poly(dimethylsiloxane) Networks Having High-Functionality Crosslinks and Bimodal Chain-Length Distributions. J.Appl. Polym. Sci. Symp. 1994, 55, 139-152. 

Sharaf MA, Mark JE, Al-Ghazal AA-R. Elastomeric properties of poly(dimethylsiloxane) networks having high-functionality crosslinks and bimodal chain-length distributions. J Appl Polym Sci Symp 1994 55 139-52. 

Interpenetrating elastomeric network Intumescent flame retardant Interpenetrating homopolymer network Elastomerie eopolymer from isobutene and isoprene (ANSI/ASTM, lUPAC) see also Butyl, GR-I, PlBl Poly(isobutylene) see also PIB Intermediate molecular weight Isophthalic acid... 

Another approach was attempted by Seppala and Kylma who reported the synthesis of poly(ester-urethane)s by condensation of hydroxyl terminated tel-echelic poly(CL-co-LA) oligomers with 1,6-hexamethylene diisocyanate (Scheme 33) [94]. The diisocyanate acts as chain extender producing an increase in molecular weight of the preformed oligomers. The authors claim that some of the copolymers present elastomeric properties. Using a similar method. Storey described the synthesis of polyurethane networks based on D,L-LA, GA, eCL,... 

In our laboratory, much attention has been devoted to the investigation of in situ sequential polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (SEQ PUR/PAc IPNs) (2- ) in which the elastomeric polyurethane network is completely formed in the presence of the methacrylic monomers before the onset of the radical copolymerization which leads to the second network. To each polymerization process corresponds a typical kinetics, which however is not completely independent from each other ( -8). The results obtained with such SEQ IPNs show that the properties do in... 

A clear trend is recognized between fiber polarity and moisture uptake. The amount of polar amide (NH-CO) linkages and hydroxyl (OH) pendant groups into the methylene chain structures of polyamide and poly(vinyl alcohol) fibers, respectively, render them significantly more moisture absorbent (4-5%) than the polyolefins and elastomeric fibers (less than 0.1%). Densely packed polymer networks, as in the cases of polyester, poly(vinyl chloride), and particularly Kevlar fibers, exclude the entry of water molecules, again resulting in low moisture content. 

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