Thesis (Ph.D.) OGI School of Science & Engineering at OHSU, January 2007. / Abstract: leaf x. Includes bibliographical references (leaves 124-138).

The allylic bromide functionality in brominated poly(isoprene-co-isobutylene) rubber (BIIR) reacted readily to nucleophilic substitution by imidazole-derivatives. When reacted with the rubber, alkylimidazoles formed a stable non-thermoset ionomeric elastomer that has dynamic mechanical properties similar to those of vulcanizates; however, the strength is in its ion-pair aggregation. Structural characterization of the polymeric products was accomplished by spectroscopy with comparisons to the model compound prepared from brominated 2,2,4,8,8-pentamethyl-4-nonene (BPMN). Physical properties tests on the elastomers of varying ionic content (0-1 mol%) were done using solution viscosity and rheology, and demonstrated that small amounts of ionic functionality noticeably improved properties with a plateau of properties being attained as full conversion to ionic content was reached. The reaction of imidazole with BIIR created a thermoset elastomer that formed an ionomer and thermoset after its second alkylation. These materials provided excellent scorch protection and delayed curing at high temperatures, while still reaching good storage modulus. Formation of an elastomer with a pendant imidazole group was also achieved; however, it did not perform as well as the free imidazole. / Thesis (Master, Chemical Engineering) -- Queen's University, 2010-10-27 11:52:54.442

Tyre inner tubes made of butyl rubber have been found to have poor heat resistance when used in the environment of Iraq. Research investigations were undertaken to establish the causes of the problem: these consisted of examining the individual contributions of oxidative scission processes in both rubber hydrocarbon and the various processing oils. The principal method used to monitor the degradation processes was ageing in hot air using the reduction in strength for the rubber and change in chemical composition of the processing oils. This preliminary study established that the processing oil made in Iraq was found to be of different composition from the common European rubber processing oils and contributed considerably to the poor life of the butyl inner tubes. Analysis of the oil from Iraq identified the presence of trace amounts of copper (3 ppm) known, from the literature, to adversely affect the resistance of many rubbers to elevated temperatures and, as found in this work, to also degrade butyl rubber. Replacement of the butyl rubber by chlorobutyl rubber overcame the problem of inner tube degradation and an antioxidant system based on a combination of an acetone/diphenylamine (ADPA) plus mercaptobenzimidazole (MBI) with MgO was found effective in minimising chlorobutyl inner tube degradation. However, unexpectedly, the research also established that trace quantities of copper were useful as stabilisers in enhancing the heat ageing properties of chlorobutyl rubber and the addition of a particular copper salt (copper sulphatel in small proportions (3 ppm) as an anti-degradant was found beneficial. Another method studied to improve the resistance of halogenated butyl rubber to heat induced oxidative degradation tried to use ZnO as the curative, as recommended by the manufacturers of chlorobutyl rubber; however it was found that with this technique higher degradation was obtained in chlorobutyl than with the standard ZnO/ sulphurless curing system (i.e. ZnO/TMTDin proportions 5:1 phr). It was concluded from these studies that: 1. Reducing the oil level in butyl inner tubes from 25 phr to 15 phr enhances heat ageing properties of the rubber. Factory trials confirmed this finding. 2. Adding a copper inhibitor (ZDC) in the proportions 1-2 phr in butyl inner tubes was found successful in minimising oxidative degradation. 3. The existence of elemental copper in a chlorobutyl inner tube rubber formulation in the proportion 3 ppm improved the rubber properties at elevated temperatures.

Thèse 3 cycle--Chimie appliquée--Paris VI, 1981. / 1981 d'après la déclaration de dépôt légal. Bibliogr. p. 118-122.

Isobutylene-rich elastomers bearing functional groups that engage N-arylmaleimides in C-H bond addition and/or alternating copolymerization are described. While inactive to cross-linking when treated at high temperature with peroxide alone, these co-curing elastomers can be cross-linked substantially when combined with bis-maleimide coagents such as N,N’-m-phenylene dimaleimide (BMI). Poly(isobutylene-co-isoprene) (IIR) samples containing relatively high amounts of residual isoprene unsaturation are shown to provide relatively low coagent cure reactivity, whereas IIR derivatives bearing pendant polyether or vinyl ether functionality are shown to provide exceptional cross-linking rates and extents when treated with identical BMI formulations. The design of such co-curing elastomers is discussed, along with the physical properties of the resulting vulcanizates. Isobutylene rich elastomers bearing oligomerizable (C=C) functional groups, macromonomers, that are activated in the presence of free-radical initiators are described. The criteria for determining the macromonomers that are best suited for preparing thermosets of IIR is discussed. While IIR derivatives bearing pendant acrylic, styrenic and maleimide functionality are shown to provide exceptional cross-linking rates and extents, they are also shown to suffer from instability in the absence of peroxide. IIR carrying pendant methacrylic and itaconate functionality are shown to provide a good balance of cure rates and stability. Nitroxyl based radical trap that provides scorch protection to the macromonomers while regenerating the cure extent is discussed. Functional macromonomer derivatives of IIR bearing containing multi-functional pendant groups are discussed. IIR derivatives with itaconate and low amounts of BHT pendant groups is shown to act as bound anti-oxidant while IIR containing pendant fluoro groups are shown to have reduced surface energy. Ionic coagents are used to cross-link IIR containing itaconate pendant groups and their physical properties are discussed. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2012-07-06 11:20:56.915

Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Science, 2009. / "May, 2009." Title from electronic dissertation title page (viewed 11/29/2009) Advisor, Judit E. Puskas; Committee members, Roderic P. Quirk, Joseph P. Kennedy, Li Jia, Chrys Wesdemiotis; Department Chair, Ali Dhinojwala; Dean of the College, Stephen Z. D. Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Ionomers bearing reactive ion-pair functionality are a novel class of materials that have been prepared. The N-alkylation of N-vinylimidazole by poly(isobutylene-co-isoprene) produced the reactive ionomer product in good yield, through a solvent-borne process. Solvent-free conditions can also be used to produce reactive ionomers by the N-alkylation of N-vinylimidazole by poly(isobutylene-co-para-methylstyrene). Characterization of these derivatives was carried out with the assistance of model compounds, and showed excellent agreement with 1H NMR spectra. These reactive ionomers readily crosslink with peroxide at elevated temperatures and in the absence of peroxide they have excellent thermal stability. The amount of crosslinking can be altered based on the vinyl content of the material, to target various applications. N-alkylation of N-vinylimidazole can be carried out concurrently with a non-reactive N-alkylimidazole to achieve desired vinyl contents and tailor the physical properties of these materials. These materials contain both ionic and covalent crosslink networks, and this hybrid network structure provides these materials with unique crosslink structures and stress relaxation properties. Conventional rubber fillers are compatible with these novel reactive ionomers. Carbon black and precipitated silica have no adverse effects on the peroxide crosslinking of the elastomers and a constant peroxide loading can be used regardless of the filler loading. Payne analysis shows good filler dispersion at low filler loading; however, there is some evidence of reticulate filler network formation at high filler loadings. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-03-31 21:12:46.618

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 165-177). Also available via the Internet.

Thesis--Helsinki. / Includes bibliographical references.

Th. doct.-ing.--Nancy, I.N.P.L., 1980.