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Polybutadiene and poly(butadiene-co-styrene) elastomers were prepared in high conversions using 2-lithio-2- methyl-1,3-dithiane as the initiator. Polymers were readily prepared with a polydispersity index (PDI) of 1.05 to 1.26 and a Mn of up to 208 kg/mol. The replacement of the 2-methyl substituent with phenyl, trimethylsilyl or 4-dimethylamino phenyl also gave active initiators that incorporated at the head of the chain. However, initiation rates appeared to vary somewhat with the structure of the initiators. The polymerizations obtained are in all cases controlled and apparently living with the live chain ends capable of further reactions. The initiators could be generated prior to addition to the polymerization mixture or by an in-situ procedure. Model studies gave evidence that the dithiane chain end can be opened under cure conditions and react with unsaturation present in the polymer chain. Several of the product polymers were found to impart improved hysteresis to carbon and silica-filled rubbery vulcanizates possibly through an endlinking mechanism.

X-ray photoelectron spectroscopy (XPS or ESCA) was used to examine the outermost 100 A˚ of selected elastomer substrates, and to classify the predominant reactions that occur there between the substrates and trichloroisocyanuric acid (TCICA). About four monolayers deep, this surface region represents the locus of interfacial and adhesive processes. From these experiments, we concluded the following: (1) at the outermost surface of NR, substitution reactions of TCICA predominate, but a minor amount of addition is also evident; (2) addition and substitution reactions compete on the surfaces of the butadiene-containing polymers, BR and SBR; (3) no detectable functionalization by TCICA takes place on EPDM or CIIR — polymers which lack sufficient olefinic sites for surface modification; (4) isocyanuric acid or other nitrogenous residues are present on treated surfaces before washing; (5) reconstruction of functionalized surfaces may occur upon swelling for extended periods; (6) surface oxygen levels in these experiments were variable, and could not be relied upon as indicators of the functionalization chemistry.

The preparation, analysis, testing, and structure determination of ultrahigh impact rubber-toughened polycaprolactams (nylon 6) are described. Partially unsaturated hydrocarbon rubbers were used for this purpose. They were functionalized by reaction either in solution or in bulk with maleic anhydride to give rubbery “ene” adducts containing varying amounts of pendnet succinic anhydride. Tough, rigid, thermoplastic engineering resins with notched Izod impact strengths of 750–1000 J/m were prepared by briefly melt-blending these adducts with nylon 6. Properties of the blends could be affected by the type and amount of elastomer used, the anhydride content, the type of nylon, the mixing conditions and the test conditions. Fractionation by coacervation in m-cresol/cyclohexane of a typical resin containing 20% by weight of functionalized rubber showed approximately 35% of a rubber–nylon graft, along with a few percent of free rubber dispersed in the nylon 6 matrix. A comb-block copolymer structure for the graft and a model for its formation are proposed, consistent with analyses of the fractions. Some of the blends prepared with partially hydrogenated medium vinyl polybutadiene–maleic anhydride adducts displayed a retention of impact properties at low temperatures which was superior to that obtainable with a similarly prepared EPDM-modified nylon 6. Transmission electron microscopy of a blend containing an anhydride-modified hydrogenated medium vinyl polybutadiene showed a morphology consisting of a nylon matrix containing finely dispersed, irregularly shaped, 0.03–0.55 μm rubber domains in which were found even smaller domains of nylon.

The relationship between ester structure and flammability was studied for a series of organophosphazene ester polymers and oligomers. Aliphatic esters showed lowest oxygen index ( OI ) values, ranging from 16 to 26. Thermogravimetric and pyrolyzate analyses suggested that this low range was due to both volatility and ready fragmentation to hydrocarbons. Non-halogenated aryloxyphosphazenes showed moderately high OI values in the range of 25–33, and flammability was similar for both polymers and corresponding oligomers. Highest OI s were found in halogenated derivatives, presumably owing to chemical inertness and stability. Differences in flammability among organophosphazene esters are rationalized in terms of degradation mechanisms followed by individual structures and the resulting fuels which are formed.

The influence of ferrocene on the flammability and smoke generation behavior and thermal characteristics of poly(vinyl chloride) (PVC) and poly(vinyl alcohol) (PVC) was examined in order to understand the basis of ferrocene's activity as a flame-retardant and smoke-suppressant additive. Ferrocene increased char formation in PVC by 20–60% while increasing the limiting oxygen index (O.I.) by 15–19%. Little char was found either with or without ferrocene in PVA, which had little improvement in O.I. Visible smoke was significantly decreased by ferrocene in PVA and in PVC of low to moderate molecular weight, but was unchanged in high molecular weight PVC. O.I. of PVC appeared to vary with molecular weight of the polymer. Thermogravimetric analyses and thermal degradation experiments showed that ferrocene promotes early weight loss and crosslinking in PVC. This effect is coincidental with the formation of ferricenium cation, which was identified by its visible spectrum and which may be a possible catalyst. Smoke inhibition of PVA by ferrocene occurs predominantly through gas-phase processes, while in PVC evidence and analogy for activity in both the gas phase and condensed phase are found.

Corona discharge in air appreciably increased surface energies of ethylene—propylene—diene rubber (EPDM), a blend of chlorobutyl and natural rubbers, and styrene—butadiene rubber (SBR), as determined by contact angle measurements. High energy surfaces were typically short-lived, on the order of minutes, presumably due to facile reconstruction of the surface by mobile elastomer chains. Surface activation occurred despite the relatively thick specimens (1.8–2.5 mm) and the presence of up to 35% by weight of carbon black. Electrode configurations had an effect on the experimental results. Ozone, a byproduct of corona discharge, eroded the surface of SBR. Modest improvements in the bonding of an elastomeric urethane coating were realized with some of the surface-activated elastomers.

A number of ketyls and semidiones containing 13C have been examined by ESR spectroscopy. Grossly different values of aCOC in the ketyls (∼ 50 G) and the semidiones (∼ 1 G) allow for an easy differentiation of the two species. This is important because strained ring ketyls can undergo a decomposition reaction leading to the semidione with one additional carbonyl group added to the ketyl. Values of aCOC, aαC, and aβC for keyls and semidiones are reporduced by the Karplus–Fraenkel equation if the term QCC′C is allowed to increase by 15% when C′ is altered from methyl to t‐butyl. No evidence for the nonplanarity of di‐t‐butyl ketyl could be deduced. Some unusual long‐range 13C hfsc (aγC) have been detected in certain bicyclic semidiones possessing a nearly coplanar, zigzag arrangement of three carbon–carbon bonds with a pz orbital.

A 1973 report of the National Commission on Fire Prevention and Control cited the flammability of materials as only one of several aspects of America’s fire problem, which also includes fire prevention, personal education, firefighting, medical treatment, building and systems design, and fire detection, containment, and extinguishment.(1) Materials, whether petroleum stocks, grains, lumber, or synthetic polymers, present a source of fuel for combustion. Historically, the chemical treatment of materials to improve fire resistance can be traced back at least as far as the eighteenth century, and the literature describing such treatments has since grown voluminous. However, smoke generation is one of the hazards associated with materials’ flammability, and this has received attention only relatively recently.