POLYMETHYL STYRENE

Thermal degradation of plastics can be classified as depolymerization, random decomposition and mid chain degradation [54, 55], In the process of depolymerization, the conjunction bonds between monomers are broken up, which leads to the forming of monomers. Depolymerization type plastics mainly include a-polymethyl styrene, polymethyl methacrylate and polytetrachloroethylene. In the random decomposition process, scission of carbon chains occurs randomly, and low-molecular hydrocarbons are produced. Random-decomposition-type plastics include PP, PVC and so on. In most cases, both decompositions take place. To be more specific, the degradation of polyolefins can be classified as the following three types ... 

Poly(vinylidene fluoride)-PEMA Poly(vinylidene fluoride)-PVMK Poly(vinylidene fluoride)-PEA Polymethyl styrene-PMMA Polycaprolactone-SAN... 

In another study, uniform composite polymethyl-methacrylate/polystyrene (PMMA/PS) composite particles in the size range of 1-10 fim were prepared by the seeded emulsion polymerization of styrene [121]. The PMMA seed particles were initially prepared by the dispersion polymerization of MMA by using AIBN as the initiator. In this polymerization, poly(7V-vinyl pyrolli-done) and methyl tricaprylyl ammonium chloride were used as the stabilizer and the costabilizer, respectively, in the methanol medium. Seed particles were swollen with styrene monomer in a medium comprised of seed particles, styrene, water, poly(7V-vinyl pyrollidone), Polywet KX-3 and aeorosol MA emulsifiers, sodium bicarbonate, hydroquinone inhibitor, and azobis(2-methylbu-... 

SBR (Styrene Butadiene Rubber) ABS (Acrylonitrile Butadiene Styrene Polymethyl methacrylate PAN (Polyacrylonitrile)... 

Another useful, and quite sensitive, test is the initiation of polymerisation (c/ p. 320). Polymerisation can be initiated, in suitable substrates, by cations and anions as well as by radicals, but the effect of these several species can be differentiated by using a 50/50 mixture of phenylethene (styrene), PhCH=CH2, and methyl 2-methyl-propenoate (methyl methacrylate), CH2=C(Me)C02Me, as substrate cationic initiators are found to produce polystyrene only, anions polymethyl methacrylate only, while radicals produce a copolymer containing equal amounts of the two monomers. 

Another differential reaction is copolymerization. An equi-molar mixture of styrene and methyl methacrylate gives copolymers of different composition depending on the initiator. The radical chains started by benzoyl peroxide are 51 % polystyrene, the cationic chains from stannic chloride or boron trifluoride etherate are 100% polystyrene, and the anionic chains from sodium or potassium are more than 99 % polymethyl methacrylate.444 The radicals attack either monomer indiscriminately, the carbanions prefer methyl methacrylate and the carbonium ions prefer styrene. As can be seen from the data of Table XIV, the reactivity of a radical varies considerably with its structure, and it is worth considering whether this variability would be enough to make a radical derived from sodium or potassium give 99 % polymethyl methacrylate.446 If so, the alkali metal intitiated polymerization would not need to be a carbanionic chain reaction. However, the polymer initiated by triphenylmethyl sodium is also about 99% polymethyl methacrylate, whereas tert-butyl peroxide and >-chlorobenzoyl peroxide give 49 to 51 % styrene in the initial polymer.445... 

ABS Acrylonitrile Butadiene Styrene SAN Styrene Acrilonitrile PMMA Polymethyl Methacrylate... 

For example, Melville [26] studied the ultrasonically induced polymerisation of monomers such as styrene, methyl methacrylate and vinyl acetate in the presence and absence of polymethyl methacrylate and found that the polymerisation rates ( 1 % conversion/h) were not substantially increased by the presence of polymer. He concluded, in contrast to Driscoll, that the degradation of polymer was not the major source of radical production. Using hydroquinone as an inhibitor, he was able to deduce, from retardation times, that the rate of radical production was 2 X 10 mol dm s. A typical value for radical production using as an example the thermal initiation of AZBN (10 mol dm ) at 60 °C is 2 x 10" mol dm s" ... 

Fig. 23. Polymerization of monomers in masticating polystyrene and polymethyl methacrylate. Curves 1-6 1 ml methacrylic acid, styrene, methyl methacrylate, ethyl acrylate, acrylonitrile, and vinyl acetate, respectively, in 3 g polystyrene. Curves 7-12 2 ml methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate, styrene, and vinyl acetate, respectively, in 3g polymethyl methacrylate. The limiting viscosity numbers for points along Curves 2 and 3...

Fig. 24. Composition during the mastication of initially (a) 24% methyl methacrylate in polystyrene and (b) 38% styrene in polymethyl methacrylate. Curves a, b, and c Free polystyrene, block polymer, and free polymethyl methacrylate, respectively. Curves d, b and c ...

Figure 15. Influence of the Polyester Yellow dye film absorbance and polymer binder material on the marking threshold energy. PnBMA = poly(n-butyl methacrylate) PiBMA = poly(isobutyl methacrylate) PS = polystyrene PsBMA = poly (sec-butyl methacrylate) PVB = polyvinylbutyl PMMA = polymethyl methacrylate PVAC = polyvinylacetate, S-iBMA = poly(styrene-co-isobutyl methacrylate), PC = polycarbonate S-AN — poly(styrene-co-...

G.E. Me Kee, M. Welz, A. Deckers, D. Wagner, P.O. Damm, and H.-J. Oslowski, Use of mixtures of polymethyl methacrylate and styrene-acrylonitrile copolymers for the production of laser-inscribed moldings, US Patent 6020106, assigned to BASF Aktiengesellschaft (Ludwigshafen, DE), February 1, 2000. 

Acrylonitrile-Butadine-Styrene (ABS) 6. Polymethyl Methacrylate (Acrylic)... 

It was found that when grafting methyl methacrylate or styrene to rubber, the branches of polymethyl methacrylate or polystyrene are much smaller than was expected, while almost 50 per cent more vinyl polymer was bound than predicted (8, 27, 129, 130, 160, 161). The length of the side branches was determined after oxidation of the rubber, usually by ozonolysis (28, 71, 131) or by perbenzoic acid oxidation followed by periodate treatment (168). 

Several graft copolymerizations were described by Ballantine (17, 64), Henglein (104, 105) and coworkers. Different monomer-polymer systems were examined styrene on polymethyl methacrylate, poly-2, 5-dichlorostyrene, polytetrafluoroethylene, polyethylene, polypropylene and polyisobutylene, acrylonitrile on polyethylene, rubber, polymethyl methacrylate and dimethyl polysiloxane, vinylpyrrolidone and acroleine on polymethyl methacrylate. The results agree with the preceding ones moreover they show the influence of the swelling and diffusion of the monomer into the polymer. 

By ultrasonic irradiation of a solution of polymethyl methacrylate in vinyl acetate or in styrene, no appreciable amount of block copolymer could be found 154). Henglein succeeded with addition of acrylonitrile to polyacrylamide dissolved in water 100). Although acrylonitrile itself... 

The mechanical degradation and production of macroradicals can also be performed by mastication of polymers brought into a rubbery state by admixture with monomer several monomer-polymer systems were examined (10, 11). This technique was for instance studied for the cold mastication of natural rubber or butadiene copolymers in the presence of a vinyl monomer (13, 31, 52). The polymerization of methyl methacrylate or styrene during the mastication of natural rubber has yielded copolymers which remain soluble up to complete polymerization vinyl acetate, which could not produce graft copolymers by the chain transfer technique, failed also in this mastication procedure. Block and graft copolymers were also prepared by cross-addition of the macroradicals generated by the cold milling and mastication of mixtures of various elastomers and polymers, such as natural rubber/polymethyl methacrylate (74), natural rubber/butadiene-styrene rubbers (76) and even phenol-formaldehyde resin/nitrile rubber (125). 

It was also described that some common vinyl polymers, such as polymethyl methacrylate prepared with benzoyl peroxide, are able to initiate a further polymerization if heated in the presence of a second monomer [158). These phenomena must be interpreted by the existence of peroxide links inside the polymethyl methacrylate chain [229). Indeed any activity is destroyed on prolonged heating and this polymer can be used for initiating the polymerization of styrene. However the relative length of the sequences and the molecular weight of the product before and after copolymerization have not yet been determined. 

For example polymethyl acrylate was treated with phosphorus penta-chloride to form copolymers containing 26.6 and 37.8% acid chloride units these copolymers, by treatment with tert-butyl hydroperoxide, yield 4.9 to 6% perester containing polymers which were used for grafting styrene, vinyl acetate, acrylonitrile (177). 

In the case of styrene the polymer contains at both ends a carboxyl group (chain termination by coupling), while polymers characterized by a termination reaction by disproportionation (polyvinyl acetate, polymethyl methacrylate) contain only one carboxyl end group. The carboxyl groups in these polymers were transformed to acid chlorides and coupled with a diol, e.g. 1,6-hexanediol. The comparison of the molecular weight of the polymers before and after condensation permits to elucidate the... 

The case of "living polystyrene and methyl methacrylate is somewhat similar. It was shown, as should be expected, that "living polymethyl methacrylate does not initiate styrene polymerization (70), i. e. methyl-methacrylate is a terminator for the latter polymerization, although its addition to living poly-styrene initiates its polymerization. Hence, one may produce a block polymer by adding methyl methacrylate to "living polystyrene but not vice-versa (9,10). 

In the polymer impregnated gels, some porosity typically remains. Although some copolymers of methyl methacrylate, butadiene and styrene have been used to impregnate silica, the best known system is still silica impregnated with polymethyl methacrylate (PMMA)150-153. While this type of hybrid was important at first, it has been surpassed by other methods of hybrid synthesis that are simpler, with fewer steps and shorter times. 

PC PE PES PET PF PFA PI PMMA PP PPO PS PSO PTFE PTMT PU PVA PVAC PVC PVDC PVDF PVF TFE SAN SI TP TPX UF UHMWPE UPVC Polycarbonate Polyethylene Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde Polyfluoro alkoxy Polyimide Polymethyl methacrylate Polypropylene Polyphenylene oxide Polystyrene Polysulfone Polytetrafluoroethylene Polytetramethylene terephthalate (thermoplastic polyester) Polyurethane Polyvinyl alcohol Polyvinyl acetate Polyvinyl chloride Polyvinyl idene chloride Polyvinylidene fluoride Polyvinyl fluoride Polytelrafluoroethylene Styrene-acrylonitrile Silicone Thermoplastic Elastomers Polymethylpentene Urea formaldehyde Ultrahigh-molecular-weight polyethylene Unplasticized polyvinyl chloride... 

Controlled grafting via heterogeneous ATRP of polymethyl methacrylate onto poly(ethylene-co-styrene) is one of the most significant advancements in the surface modification of PE [199]. The grafting of PMMA was carried out in presence of CuBr and pentamethyldiethylenetriamine as a catalyst via the well-known ATRP mechanism, as shown in Scheme 13. 

Figure 7.5 Classification result of shredded mixed electronics waste, superimposed onto a greyscale image of the waste fraction. Only objects that could be identified with a likelihood >95% have been classified. Classification colour code yellow metal, mostly aluminium red polymethyl metacry-late (PMMA) orange polyolefines (PE, PP) pink styrene polymers (PS, PS-E, etc.) violet polyamides (PA 6, PA 6.6, etc.) green acrylonitrile-butadiene-styrene (ABS) blue polyvinyl chloride (PVC).

Polychlorobutene Polymethyl-metacrylate Styrene-butadiene copolymer Vinyl acetate-acrylic copolymer... 

Chain polymerization (addition reactions) polyoxymethylene, polymethyl methacrylate (PMMA), acrylic polymers, polystyrene and styrene copolymers, water-soluble polyamide... 

Zilkha, Neta, and Frankel (105) polymerized acrylonitrile and methyl methacrylate with sodium-benzophenone ketyl. They found that polymethyl methacrylate anion initiated acrylonitrile With a mixture of styrene and acrylonitrile, no copolymer was formed. 

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