Styrene-isoprene-methyl methacrylate

Figure 34 TEM image of a styrene-isoprene-methyl methacrylate (SIM) star SIM-57/85/49 stained with OSO4. The dark regions correspond to the polyisoprene phase that forms rhomboid columns. (Reproduced from Ref. 131. American Chemical Society, 1998.)...

When the metallated polymer 16/17 was reacted with dimethoxychlorosilane the resulting polymer was demonstrated to be moisture curable. Graft copolymers have also been synthesized from the metallated polymers 16/17 " by reaction with styrene, isoprene, methyl methacrylate, hexamethylcyclotrisiloxane and phenyl isocyanate. 

Tureau MS, Epps TH (2009) Nanoscale networks in poly[isoprene-block-styrene-block-(methyl methacrylate)] triblock copolymers. Macromol Rapid Commun 30 1751-1755... 

A topochemical condition for polymerization is the proper approach of successive monomers at the growing chain-end within the channels. In this respect, conjugated dienes like butadiene, isoprene, etc. possessing reactive atoms in terminal positions, are very suited to inclusion polymerization. However, even bulkier monomers such as substituted styrenes or methyl methacrylate can polymerize if the space available inside the channels permits a favorable orientation and/or conformation of the monomer. The most studied examples are butadiene, vinyl chloride, bromide and fluoride, and acrylonitrile in urea 2,3-dimethylbutadiene and 2,3-dichlorobutadiene in thiourea butadiene, isoprene, cis- and trans-pentadiene, trans-2-methylpentadiene, ethylene and propylene in PHTP butadiene, cis- and trans-pentadiene, cis- and trans-2-methylpentadiene in DCA and ACA butadiene, vinyl chloride, 4-bro-mostyrene, divinylbenzene, acrylonitrile and methyl methacrylate in TPP. 

Antioxidants based on 2,6-ditertiarybutyl- -vinylphenol or 2,6-ditertiarybutyl-l-isopropenylphenol are the only monomeric stabilizers that have been synthesized and studied. We have developed efficient synthetic methods for the preparation of such compounds and have polymerized them with styrene or methyl methacrylate in solution or in bulk with AIBN as the initiator. More importantly, we have developed a good emulsion polymerization of 2,6-ditertiarybutyl-4-vinylphenol and 2,6-ditertiarybutyl-4-isopropenylphenol with butadiene or isoprene. The copolymers of good molecular weights had comonomer contents between 6 mol and 20 mol of the vinyl or iso-propenyl monomer. The polymers were effective at a 0.1 weight percent level in retarding autooxidation of polybutadiene and polyiso-prene. 

Cross-linking by addition polymerization is also used to a considerable extent. Unsaturated polyesters are cross-linked by copolymerization with styrene or methyl methacrylate. Cross-linking soft, natural rubber with sulfur gives the normally used hard, vulcanized rubber. Ethylene-propylene rubbers can be cross-linked with peroxides. The cross-linking of elastomers is also called vulcanization, since the classic cross-linking of natural rubber, cis-l,4-poly(isoprene), uses heat and sulfur, which were the elements assigned to the god Vulcan (see also Chapter 37). 

For example, methyl methacrylate block copolymers are much less studied than those of styrene. Anion chain transfer occurs at the pendent ester group, drastically reducing the yield of block copolymers. Poly(methyl methacrylate-b-isoprene) has been prepared, however, by using an ingenious chain cap of l,l -diphenylethyl-ene(27,28). i l diphenylethylene will not anionically homopolymerize, therefore it adds only one mer to the macroanion. This anion is more stable in the presence of methyl methacrylate, but will initiate further polymerization. Other workers have reported the preparation of isoprene-methyl methacrylate block copolymers by sequential addition to "living" polyisoprene anions(29,30),... 

P(HB-b-I-S) Block copolymer of hydrogenated butadiene, isoprene, and styrene P(S-b-MMA) Block copolymer of styrene and methyl methacrylate PA Polyamide... 

Photoreactions of MA with 1,2-polybutadiene, 1,4-polybutadiene, poly(styrene-co-butadiene), poly(styrene-co-isoprene), polystyrene, and poly(styrene-co-methyl methacrylate) have been studied in air. " In homogeneous solutions, MA addition to the polymers proceeds efficiently by a chain mechanism, where the quantum yield of the photoaddition was greater than unity under irradiation at A >310 nm. From the effects of solvent and photosensitizers and spectroscopic data, a radical chain mechanism was proposed to account for addition and crosslinking of the polymers by MA molecules. The photoaddition reaction was applied to the surface of polymer films. The photoreactions were conducted at the interphase between solid polymer and acetone solution of anhydride and also at the interphase between solid polymer and gaseous anhydride. Irradiation with a 300-W high-pressure lamp brought about considerable surface modification, as shown by wettability and dyeability properties. 

Winnik et al. [53] used time-resolved fluorescence spectroscopy (direct non-radi-ative energy transfer experiments) to determine the interface thickness in films of symmetric poly(styrene-fc-methyl methacrylate) (PS-PMMA) block copolymers labeled at their junctions with either a 9-phenanthryl or a 2-anthryl group. The corrected donor fluorescence decay profiles were fitted to simulated fluorescence decay curves in which the interface thickness 8 was the only adjustable parameter. The optimum value of the interface thickness obtained was 6 = 4.8 run. In similar studies [54—57], the same authors determined the interface thickness value 6 = 1.6 nm in mixtures of two symmetrical poly(isoprene-b-methyl methacrylate) (PI-PMMA) block copolymers of similar molar mass and composition [54] the interface thickness value 8 = 1.1 nm for the lamellar structures formed in films of symmetric PI-PMMA diblock copolymers bearing dyes at the junctions [55] a cylindrical interface thickness value of d slightly smaller than 1.0 nm in films consisting of mixtures of donor- and acceptor-labeled PI-PMMA (29vol% PI) that form a hexagonal phase in the bulk state [56] and the interface thickness 8 = 5 run on the diblock copolymer poly(styrene-l>-butyl methacrylate)(PS-h-PBMA) [57]. 

A number of typical polymer-forming monomers have been polymerized using plasma polymerization including tetrafluoroethylene, styrene, acrylic acid, methyl methacrylate, isoprene, and ethylene. Polymerization of many nontypical monomers has also occurred including toluene, benzene, and simple hydrocarbons. 

Many substituents stabilize the monomer but have no appreciable effect on polymer stability, since resonance is only possible with the former. The net effect is to decrease the exothermicity of the polymerization. Thus hyperconjugation of alkyl groups with the C=C lowers AH for propylene and 1-butene polymerizations. Conjugation of the C=C with substituents such as the benzene ring (styrene and a-methylstyrene), and alkene double bond (butadiene and isoprene), the carbonyl linkage (acrylic acid, methyl acrylate, methyl methacrylate), and the nitrile group (acrylonitrile) similarly leads to stabilization of the monomer and decreases enthalpies of polymerization. When the substituent is poorly conjugating as in vinyl acetate, the AH is close to the value for ethylene. 

Thus, the synthesis of a styrene-methyl methacrylate block polymer requires that styrene be the first monomer. Further, it is useful to decrease the nucleophilicity of polystyryl carbanions by adding a small amount of 1,1-diphenylethene to minimize attack at the ester function of MMA [Quirk et al., 2000]. Block copolymers of styrene with isoprene or 1,3-butadiene require no specific sequencing since crossover occurs either way. Block copolymers of MMA with isoprene or 1,3-butadiene require that the diene be the first monomer. The length of each segment in a block copolymer is controlled by the ratio of each monomer to initiator. The properties of the block copolymer vary with the block lengths of the different monomers. 

Penultimate effects have been observed for many comonomer pairs. Among these are the radical copolymerizations of styrene-fumaronitrile, styrene-diethyl fumarate, ethyl methacrylate-styrene, methyl methacrylate l-vinylpyridine, methyl acrylate-1,3-butadiene, methyl methacrylate-methyl acrylate, styrene-dimethyl itaconate, hexafluoroisobutylene-vinyl acetate, 2,4-dicyano-l-butene-isoprene, and other comonomer pairs [Barb, 1953 Brown and Fujimori, 1987 Buback et al., 2001 Burke et al., 1994a,b, 1995 Cowie et al., 1990 Davis et al., 1990 Fordyce and Ham, 1951 Fukuda et al., 2002 Guyot and Guillot, 1967 Hecht and Ojha, 1969 Hill et al., 1982, 1985 Ma et al., 2001 Motoc et al., 1978 Natansohn et al., 1978 Prementine and Tirrell, 1987 Rounsefell and Pittman, 1979 Van Der Meer et al., 1979 Wu et al., 1990 Yee et al., 2001 Zetterlund et al., 2002]. Although ionic copolymerizations have not been as extensively studied, penultimate effects have been found in some cases. Thus in the anionic polymerization of styrene t-vinylpyri-dine, 4-vinylpyridine adds faster to chains ending in 4-vinylpyridine if the penultimate unit is styrene [Lee et al., 1963]. 

Discuss the use of homogeneous versus heterogeneous reaction conditions for the coordination and traditional Ziegler-Natta polymerizations of propene, isoprene, styrene, methyl methacrylate, and n-butyl vinyl ether. 

Various Ln amides have already been described in Sections 4.3.5 and 4.3.6 as catalysts for polymerisation of ethylene," I38,i4i i43 jjex-l-ene, isoprene,styrene, " methyl methacrylate or other polar monomers such as t-butyl acrylate or acrylonitrile, . 138,143,152,177 nng-opening polymerisation catalysts for e-caprolactone or... 

Guzman (53) investigated the ceric ion initiated grafting of acrylonitrile, acrylamide, methyl methacrylate, styrene, vinyl acetate, methacrylate, acrylic anhydride, and isoprene to cellulose. Intense grafting was obtained with acrylonitrile, acrylamide, methacrylate and acrylic anhydride. 

The dithiocarbamates have the pentacoordinate binuclear structure (44). The diamyl- and diethyl-dithiocarbamate complexes have been found to inhibit the hardening of asphalt, but the effect appears too weak to be useful.127 The latter complex is an effective antioxidant for polyethylene,128 polypropylene,129 polystyrene,130 poly(methyl methacrylate)130 and an isoprene-styrene copolymer.131 The di-n-butyldithiocarbamate complex is important in the vulcanization and injection moulding of rubber,132 as a stabilizer against photolytic and thermal degradation. 

This group covers polymeric peroxides of indeterminate structure rather than polyfunctional macromolecules of known structure. These usually arise from autoxidation of susceptible monomers and are of very limited stability or explosive. Polymeric peroxide species described as hazardous include those derived from butadiene (highly explosive) isoprene, dimethylbutadiene (both strongly explosive) 1,5-p-menthadiene, 1,3-cyclohexadiene (both explode at 110°C) methyl methacrylate, vinyl acetate, styrene (all explode above 40°C) diethyl ether (extremely explosive even below 100°C ) and 1,1-diphenylethylene, cyclo-pentadiene (both explode on heating). 

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