Methylmethacrylate, polymerisation

Optimising polymerisation reactors can cause major controllability problems. Lewin and Bogle [28] showed how optimising a methylmethacrylate polymerisation reactor brought the operating conditions much closer to the bifurcation point which causes major problems with controlling to this set point. The use of the disturbance condition number indicated this problem. The effects are nonlinear which is reflected in different linearised measures at different operating points. The problem also exhibits input multiplicity conditions. 

Fig. 4.15), are active for ATRP of both styrene and methylmethacrylate (MMA) [46]. Polymerisation was well controlled with polydispersities ranging from 1.05 to 1.47. The rates of polymerisation 1 x 10 s ) showed the complexes to be more active than phosphine and amine ligated Fe complexes, and were said to rival Cu-based ATRP systems. It was quite recent that Cu(I) complexes of NHCs were tested as ATRP catalysts [47]. In this work, tetrahydropyrimidine-based carbenes were employed to yield mono-carbene and di-carbene complexes 42 and 43 (Fig. 4.15), which were tested for MMA polymerisation. The mono-carbene complex 42 gave relatively high polydispersities (1.4-1.8) and a low initiation efficiency (0.5), both indicative of poor catalyst control. The di-carbene complex 43 led to nncontrolled radical polymerisation, which was ascribed to the insolubility of the complex. 

Apart from trimethylborate, other trialkyl- and triarylborates, as well as alkylboron acids, are used. E.g., trialkylborates are good catalysts for the polymerisation of acrylonitrile, methylmethacrylate, styrene, vinylacetate, vinylchloride, vinylidenchloride, etc. The polymerisation of these monomers requires traces of oxygen. Oxygen seems to transform part of trial-kylborate into peroxide, which reacts with unoxidised trialkylborate and forms free radicals initiating polymerisation. 

Methyl methacrylate polymerises in the solid state to give an amorphous poly(methylmethacrylate), as do a number of other methacrylate monomers. Poly(oxymethylene) is a fibrous, oriented, crystalline polymer that is obtained by the ring opening polymerisation of cyclic oxymethylenes, -(CH20)-m, where m can be between 3 and 6. 

Polyacrylamides can be synthesised by two methods, either polymerisation of an acrylamido monomer or chemical modihcation of another polymer e.g., poly(methylmethacrylate). In the latter case CP/MAS NMR spectra show clearly the loss of —OCH3 groups as these are replaced by —NHCH2— groups (Fig. 15.2.36). 

Methylmethacrylate (MMA) is the building block for a wide range of products. It polymerises easily to form transparent resins and polymers, e.g. kitchen and bathroom surfaces, co-polymerises with other monomers, and is used in paints and coatings. 

The selected monomers are acrylonitrile (ACN), styrene, a-methyl styrene methylmethacrylate, hydroxyalkyl acrylates and methacrylates, vinyl chloride and others [1-10, 13-18]. The most favoured monomers for industrial production of graft polyether polyols are ACN and styrene [1-10, 18-29]. The resulting products from the radical polymerisation of vinylic monomers in polyethers are opaque, generally white dispersions (except those derived from ACN, which are yellow dispersions). A graft polyether polyol has three polymeric components ... 

The results clearly show that the photoinitiating activity of the water soluble benzophenone in the presence of an amine is mainly associated with the ability of the lowest excited triplet - state to abstract an electron from the amine co-synergist via an intermediate exciplex shown in Scheme I. The radical anion will then induce hydrogen atom abstraction to give a ketyl radical and an alkylamino radical. The latter is mainly responsible for inducing polymerisation of the acrylic monomer and supports earlier work on the benzophenone-triethylamine tetramine-induced photopolymerisation of methylmethacrylate during which terminal amine groups were detected (2 ) ... 

It is also noted that the polymerisation of methylmethacrylate has been observed with the cobalt complex Tp CoMe (28) (70 °C, benzene), though the efficiency of this process has not been investigated. Similarly, acrylonitrile has been polymerised in the presence of Tp CoEt (29), giving 23% polyacrylonitrile with a molecular mass of 51,000. ... 

Monomethyl maleic ester of epoxidised soybean oil (MESO) is prepared by the reaction of epoxidised oil with monomethyl maleate with AMC-2 catalyst. (AMC-2 is a mixture of 50% trivalent organic chromium complexes and 50% phthalate esters). This MESO is photo-polymerised with ultraviolet light and free radically homopolymerised and copolymerised with styrene, vinyl acetate and methylmethacrylate. MESO may also be reacted with maleic anhydride at the newly formed hydroxyl groups to give maleinised MESO. Thus a large number of resinous systems may be made from the epoxidised oil. 

The liquid acrylics form a further group of unsaturated reactive resins and these are now available as two-part mixed or unmixed products. Compared with polyesters they are a relatively recent addition to the range of adhesives potentially suitable for structural joints. Many are based on the monomer methylmethacrylate which is polymerised by the addition of a small quantity of initiator or hardener. 

Ni, X., Zhang, Y. and Mustafa, I. (1999). Correction of polymer particle size with droplet size in suspension polymerisation of methylmethacrylate in a batch oscillatory baffled reactor. Chem. Eng. ScL, Vol. 54, pp. 841-850. 

Polymethylmethacrylate with end -butylaminoxyl gronps was synthesised by a similar method [110]. However, anionic polymerisation of methylmethacrylate is accompanied by side reactions influencing the efficiency of the process (especially on the site of label attachment). The optimal conditions of synthesis are using THF as the solvent, 70 C, and initiators n-butyl lithium, sodium naphthalate or 9-lithium fluorine. In these conditions, one can obtain polymethylmethacrylate with the end AR ... 

If gaseous monomers such as ethylene or vinyl chloride are used, the production processes involve polymerisation at high pressures and the polymers formed are commonly referred to as pressure polymers , e.g. copolymers of VA/E or terpolymers of VA/E/VC or VA/E/2-EHA (2-ethylhexyl acrylate). Other non-gaseous monomers may be polymerised together to form polymers in low pressure systems and these polymers are commonly referred to as conventional polymers or atmospheric polymers , e.g. VA homopolymers, Ac polymers of methylmethacrylate. Furthermore, the use of other functional monomeric units to give the polymer specific application properties, such as cross linking in cured textile fabric applications (e.g. V-methylol acrylamide, acrylamide and many others), are often employed and these polymers are commonly referred to as speciality polymers . Common to all polymerisation reactions the processes are usually carried out in a batch-wise system, but continuous processes can also be employed. 

The samples could be divided into two groups, those for which the methylmethacrylate (MMA) event peaked near 400 °C, and which had significant methanol and carbon dioxide profiles and those for which the MMA event peaked near 370 °C, and which yielded only traces of methanol and carbon dioxide. The former group contains those materials in which the crosslink is formed in a secondary condensation reaction, usually between two copolymer chains. In the latter group, crosslinks are formed in the addition polymerisation process by incorporation of polyfunctional vinyl compounds. 

The carbene complexes [Ru(ti -C6Me6)(PMe3)(Cl)(=C 0Me CH2CH2CH2OY)]PF6. where Y is inter alia CCXT Me =CH2, COCH=CH2, CH2C Me)=CH2, can be co-polymerised with methylmethacrylate to a degree of ca. 50.218... 

Methylmethacrylate and styrene can be bulk-polymerised by heating in presence of a peroxide catalyst ... 

Add a pinch (20-30 mg) of lauroyl peroxide to 3-4 ml of methylmethacrylate taken in a hard glass test tube and shake to dissolve. Using a clamp stand, secure the test tube in a water bath maintained at 60°C. As the polymerisation progresses, the liquid in the test tube slowly starts thickening and in about one hour changes to a transparent solid. 

The iron species [Fe(X)2 CN(PP)CH(Me) = CH(Me)N(Pr ) ] (X = Cl, Br), containing highly donating imidazolyidene ligands, have been found to be extremely active and efficient catalysts for the atom transfer radical polymerisation of styrene and methylmethacrylate. A variety of indenyl ruthenium complexes containing either phenylacetylide (C = CPh) or vinyl (CH = CHPh) ligands have been found to catalyse the dimerisation of phenylacetylene to ( )-and (Z)-l,4-diphenyl-l-en-3-yne with the activity of the catalyst dependent upon the nature of the phosphine co-ligand bound to ruthenium. The vinylidene-ruthenium(II) complexes [Ru(Cl)(L)2(C = CHR)] (R = Bu, ferrocenyl L =... 

Contrary to what many people think, PLSNs are not a recent discovery. One of the earliest systematic studies of the interaction between a clay mineral and a macromolecule dates backs to 1949, when Bower described the absorption of DNA by montmorillonite. Even in the absence of X-ray diffraction (XRD) evidence, this finding implied insertion of the macromolecule in the lamellar structure of the silicate. In the case of synthetic polymers, Uskov found in 1960 that the softening point of polymethylmethacrylate derived by polymerisation of methylmethacrylate was raised by montmorillonite modified with octadecyl-ammonium, while in the following year Blumstein obtained a polymer inserted in the structure of a montmorillonite by polymerising a previously inserted vinyl monomer. In 1965 Blumstein first reported the improved thermal stability of a PMMA/clay nanocomposite. He showed that PMMA inserted between the lamellae of montmorillonite clay resisted thermal degradation under conditions that would otherwise completely degrade pure PMMA." ... 

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