Polymethyl methacrylate, preparation

B. M. Ginzburg, L. A. Shibaev, V. L. Ugolkov, Effect of fullerene C60 on thermal oxidative degradation of polymethyl methacrylate prepared by radical polymerization, Russian Journal of Applied Chemistry, vol. 74, pp. 1329-1337, 2001. 

According to this scheme, polymethyl methacrylate prepared in the absence of p benzoquinone should contain one initiator fragment per polymer molecule the addition of p benzoquinone to the polymerizing system should make this number tend towards two and at the same time the amount of combined quinone should approach one molecule per polymer molecule. Experiments with labelled initiator and labelled retarder (39) confirmed these predictions in general although not in detail. 

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. 

Table 4 shows the analyses of the spectra of a number of free radical polymethyl methacrylates prepared under conditions varying as indicated the spectra are interpreted in terms of the proportions of i, h, and s units. In Fig. 14, these results have been fitted to the probability curves by placing the s points on the curve and letting the other points fall where they may. 

FIGURE 13.6 H NMR spectra (60 MHz) of polymethyl methacrylate prepared under conditions is which the sample in a is primarily syndiotactic, and that in b is primarily isotactic. From Bovey.122... 

Polymethyl acrylate can be hydrolysed rapidly and completely under alkaline conditions. On the other hand, the monomer units in polymethyl methacrylate prepared and treated similarly are resistant to hydrolysis [51] although benzoate end-groups react readily [52]. Only about 9% of the ester groups in polymethyl methacrylate reacted even during prolonged hydrolysis hydrolysis of polymethyl acrylate was complete in 0.5 hours. Although only about 9% of the ester groups in methyl methacrylate homopolymers are hydrolysed in several hours reflux with alcoholic sodium hydroxide, this proportion is increased by the introduction of comonomer units into the polymer chain. Thus, saponification techniques should be applied with caution to polymeric materials. 

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-... 

One such reported example is the synthesis of polypropylene-6-polymethyl-methacrylate (PP-6-PMMA) copolymers utilizing metallocene catalysis and the borane chemistry. In the initial step, PP with chain-end olefinic unsaturations was prepared using metallocene catalysts such as Et(Ind)2ZrCl2/MAO. The unsaturation sites were then hydroborated by 9-borabicyclo[3.3.1]nonane (9-BBN) to produce borane-terminated PP (43) (Fig. 30), which was selectively oxidized and interconverted to a... 

Both isotactic and syndiotactic polymethyl methacrylate have been prepared. However, the commercial polymer is generally atactic because of the random arrangement of the bulky side groups. 

Block and graft copolymers were prepared by Akutin, Parlashke-vich, Kogan, Kalinina, and Menes (128) by the use of ultrasonics on solutions of fluorine containing polymers or polysiloxanes on one hand and polymethyl methacrylate, polyvinyl chloride, ethylcellulose on the other. 

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). 

Polyacrylic acid stabilised latices have been prepared by aqueous dispersion polymerisation. The method used is analogous to the non-aqueous dispersion (NAD) polymerisation methods originally used to prepare polymethyl methacrylate particles in aliphatic hydrocarbons (1. In effect the components of a NAD polymerisation have been replaced as follows aliphatic hydrocarbon by aqueous alcohol, and degraded rubber, the stabiliser, by polyacrylic acid (PAA). The effect of various parameters on the particle size and surface charge density of the latices is described together with details of their colloidal stability in the presence of added electrolyte. 

Monomer droplets are suspended in the water through the use of agitation and stabilizers, such as methyl cellulose, gelatin, polyvinyl alcohol, and sodium polyacrylate.32 Typical droplet sizes are 0.01-0.5 cm. A monomer soluble initiator is added to begin the polymerization. The kinetics of suspension polymerization are the same as for bulk polymerization, but suspension polymerization offers the advantage of good heat transfer. Polymers such as polystyrene, PVC, and polymethyl methacrylate are prepared by suspension polymerization. 

As mentioned above, the ability to have living polymerizations offered the potential to make block copolymers. In the preparation of a block copolymer the sequence of addition can be important to ensure that the second monomer is capable of adding to the living end. An example is the formation of a polystyrene—polymethyl methacrylate block copolymer.38 In this case polystyrene is polymerized first, followed by addition of the methyl methacrylate. The block copolymer could not be formed if methyl methacrylate were polymerized first, as styrene will not add... 

Electron microscopy samples were prepared by techniques similar to that of Kato (8). Film samples were fixed with OSO4, potted in polymethyl methacrylate and then microtomed into thin sections ( 100 nm) for transmission examination using a Philips 100B electron microscope. 

A method for preparing isolatable and re-activatable polymethyl methacrylate using the chain transfer agent bis(ethoxythiocarbonyl)disulfane with 2,2 -azobis(isobutyr-onitrile) is described. Reactivation of this macroinitiator with 2,2 -azobisisobutyr-onitrile was then used to prepare block copolymers. 

Alkyl a-acetoxyacrylate intermediates were prepared by condensing pyruvate derivatives with acetic anhydride and then free radically converting them into the corresponding homo- or copolymers. All copolymers had thermal properties that were superior to that of polymethyl methacrylate. In addition poly(ethyl a-acetoxy-acrylate) homopolymers were injection moldable at 250°C. 

The latest vinylferrocene monomer / -C5H4CH202CC(CH3) = CH2 rj -C5H4CH = C(CN)C02Et Fe 15 that undergoes radical polymerization has been prepared as shown in Scheme 10-3 [17] Copolymerization of the monomer with methyl methacrylate produced copolymer 16, via radical initiation using AIBN in benzene. The ethyl a-cyanoacrylate moiety on the ferrocene remained intact through the polymerization process. The thermal behavior of 16 was similar to that of polymethyl methacrylate glass transition temperature, 7 120 °C, melt transition... 

The newer type of colloidal catalysts have been prepared containing palladium (4), platinum (4), rhodium (5), and iridium (6). A variety of synthetic polymers has been applied. Among those tested were polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), and polymethyl acrylate (PAMA). In general, polyvinyl alcohol (4a) has been found most satisfactory. 

Polysulfone membranes were prepared from 12.5, 13.75, and 15% (wt. %) polysulfone solution in dimethylformamide and formed on the surface of porous, sintered polymethyl methacrylate bars. An effective surface of each membrane was 49.2 cm. The effect of some casting parameters (composition and the temperature of the casting solution, time of solvent evaporation) and the pressure applied on the transport and separation properties of the membranes were analyzed. The experiments were carried out in a 1.2 dm pressure apparatus with continuous circulation of the permeate between feeding tank and the apparatus. It was found that membranes cast from 12.5% polysulfone solution of a temperature of 298 K with no solvent evaporation displayed the best properties. After 160 hours of operation at 0.18 MPa, the membranes in question showed an ability of a 97 to 99% rejection of 781.2 molecular-weight dye. The volume flux of the dye solution varied from 0.6 to 0.8m /m per day. 

Studies of the different behavior of mono- and bi-functional living polymethyl methycrylate were reported by Hocker and co-workers373,3745. Sodium salt of monofunctional living polymethyl methacrylate was prepared in THF at low temperature by utilizing the adduct of benzyl sodium to a-methyl styrene as an initiator,... 

Many modem composite materials are prepared by microemulsion methods. Polyaniline was prepared by one-step micellar chemical polymerisation of aniline with dodecyl benzene sulfonic acid via complex formation [297]. A transparent polyaniline suspension was made by dispersing polyaniline in m-cresol. Polyaniline composites blended with polymethyl methacrylate (PMMA) exhibits relatively high conductivity at low polyaniline volume fractions and keeps good mechanical properties equivalent to those of PMMA. It should be noted that most methods proposed for the preparation of new materials are at a laboratory level, however, a widespread commercial use can be predicted for the next decade. 

The wear behaviour of polytetrafluoroethylene (PTFE), carbon-filled PTFE, high density polyethylene (HDPE), ultrahigh molecular weight polyethylene (UHMPE), low density polyethylene (LDPE) and polymethyl methacrylate (PMMA) was studied. To ensure consistent and controlled properties of the samples, many of the materials were processed in the authors laboratory. The details of sample preparation and processing techniques are reported elsewhere ( ). ... 

Contact lenses are the most common polymer product in ophthalmology. The basic requirements for this type of materials are (T)excellent optical properties with a refractive index similar to cornea good wettability and oxygen permeability ( ) biologically inert, degradation resistant and not chemically reactive to the transfer area ( ) with certain mechanical strength for intensive processing and stain and precipitation prevention. The common used contact lens material includes poly-P-hydroxy ethyl methacrylate, poly-P-hydroxy ethyl methacrylate-N-vinyl pyrrolidone, poly-P-hydroxy ethyl methacrylate, Poly-P-hydroxy ethyl methacrylate - methyl amyl acrylate and polymethyl methacrylate ester-N-vinyl pyrrolidone, etc. The artificial cornea can be prepared by silicon rubber, poly methyl... 

Methyl methacrylate (MMA) and sodium styrene sulfonate (SSNa) are water-soluble. These polymers behave like a low MW surfactant as they form micelles in aqueous solution in which the hydrophobic part is directed towards the centre and the hydrophilic part is situated on the periphery of the micelle. Owing to such features, amphiphilic block copolymers have wide-ranging applications in drugs, pharmaceuticals, coatings, cosmetics and paints. They also exhibit very high antibacterial activities. Oikonomou and co-workers used ATRP to prepare amphiphilic block copolymers, consisting of polymethyl methacrylate (PMMA) and poly (sodium styrene sulfonate) (PSSNa) blocks [18]. The synthesis methods are described below. 

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