Styrene-containing copolymers

The backbone of acrylonitrile-styrene copolymers containing more than 60% AN is characterized by ... 

In this work, studies were made on the photochemistry of styrene copolymers containing minor amounts (2-7%) of MVK, MIPK and tBVK. The properties of these polymers are summarized in Table I. The low concentrations of carbonyl units present should minimize the effects of energy... 

Dioxiranes constitute a new class of organic peroxides that possess great potential as oxidants with a variety of applications in synthetic organic chemistry.5 7 A new convenient route for the synthesis of silanol polymers has been developed by the selective oxidation of =Si—H bonds with dimethyldioxirane. A series of styrene-based silanol polymers and copolymers were synthesized (Scheme l).8 9 The precursor polymers and styrene copolymers containing =Si—H bond were first synthesized by free radical polymerization of the corresponding monomers or copolymerization of the... 

Structure and Composition of Diene Copolymers. One finds that most of the reported copolymerization studies on butadiene or isoprene involve styrene as comonomer. In part this is due to the early interest in styrene-butadiene synthetic rubbers. The free radical produced copolymers (GRS, usually about 20—25% styrene units) contain about 20% of its butadiene fraction in the 1,2 form. The ratio of 1,2 to 1,4 units is little affected by polymerization variables such as temperature, conversion and styrene content (39). Butadiene and styrene copolymers contain 50 to 60% 1,2-diene units when prepared by sodium catalysts at 50° (39). This behaviour is once more significantly different when lithium is used in place of sodium as can be seen in Table 3. 

In solution and in the rubbery state, the thermal cis-trans recovery follows first-order kinetics in the glassy state, however, some azo groups react anomalously fast, others isomerize much slower, nearly as in solution. These data confirmed earlier observations of Paik and Morawetz in the case of methyl methacrylate-styrene copolymers containing azobenzene side groups. ... 

The development of styrene technologies was mainly driven by demand for cheap synthetic rubber during and immediately after World War II. Between 5% and 10% of total styrene produced becomes a component of synthetic rubbers, which are copolymers of styrene and butadiene (SBR). Styrene copolymers containing acrylonitrile are specialty materials that are used for specific applications. Demand for styrene for the period 2004-2009 is estimated to grow at a rate of approximately 4 /o per year. ... 

For example, when the seven-membered ketene acetal V was copolymerized with styrene, a styrene copolymer containing ester groups in the backbone was obtained (r. 021 and r2 22.6). 

Figure 36 Absorption spectra of the C g-styrene copolymers containing (in the direction of increasing e values) 0.4%, 1.7%, -14%, -30%, and -50% (wt/wt) in dichloromethane. Shown in the insert are the spectra normalized at 350 nm.

Further confirmation of the important effect of solid-phase transitions in polymer photochemistry was reported by Dan and Guillet (29). They studied the quantum yields of chain scission, c >s, as a function of temperature in thin solid films of vinyl ketone homo- and copolymers. For polymers where the Norrish type-II mechanism was possibici large increases in n were observed at and above the glass transition T. Figure 8 shows this effect in a styrene copolymer containing about 5% phenyl vinyl ketone (PVK). Below Tg, )s is about 0.07, but at Tg it rises to about 0.3, a value similar to that observed for photolysis in solution at 2S°C. A similar effect was observed with poly (methyl methacrylate-co-methylvinyl ketone) (PMMA-MVK) and PVK homopolymer. 

Figure 7.38 Thermomechanical curves for (1-3) styrene copolymers containing (1, 2) 3% DVB and (5) 34% DVB, (6) polydivinylbenzene, and (3, 4) hypercrosslinked network prepared by crosslinking styrene-0.57% DVB copolymer with monochlorodimethyl ether to 100% Loading (2, 4, 5) lOg and (1, 3, 6) 400g per bead. (Reprinted from [202] with permission of Wiiey Sons, inc.)...

Example 4.1 What is the Tg of butadiene-styrene copolymer containing 10 vol% styrene ... 

Normal second order kinetics were observed for 2-methy1-5-vinyl-pyridine and 4-vinylpyridine-styrene copolymers containing up to 20 mole % pyridine units, moreover, within experimental error, the... 

Figure 4.27 Polymer backbone based on C NMR data microstructures with corresponding ethylene styrene copolymer containing 35 wt% styrene microstructure composition [59].

Table 3.3 Suggested formulations for antioxidant content for styrene copolymers containing butadiene [86]...

UV light results in yellowing and embrittlement of SB (styrene-butadiene copolymer) and SBS (styrene-butadiene block copolymer) as it does with other styrene copolymers containing butadiene [83]. Increased hydrophobicity is an important consequence of photo-induced degradation of SBS block copolymers [668]. Therefore, water absorption increases significantly in this material and its mechanical properties decrease considerably as a result. 

NMR spectra of a starting styrene/B-styrene copolymer containing 1 mol % B-styrene units (after hydroxylation) and two corresponding SPS-g-PMMA graft copolymers with 20 and 59 mol % MMA contents, respectively. In addition to the major peaks at 1.32,1.85,6.65, and 7.15ppm for the protons in the SPS backbone, the distinctive peak at 3.58ppm corresponds to methoxyl groups (CH3-O) in the PMMA. 

Amorphous plastics are basically transparent (exceptions styrene copolymers containing butadiene (B), such as SB and ABS). Amorphous plastics have lower shrinkage values than semi-crystalline compounds, so with amorphous compounds higher levels of accuracy can be obtained at lower cost than with semi-crystalline materials. 

We have already indicated that incompatibility in polymer blends causes distinct regions called microphases. The most important factor governing the mechanical properties of blends is the interfacial adhesion between microphases. One of the techniques to improve this adhesion is to bind the separate microphases through chemical reaction of functional groups. Figure 2.3 shows a styrene copolymer containing oxazoline groups and an ethylene copolymer with acryhc acid as a comonomer. These polymers are represented as follows ... 

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