Allyl methacrylate, polymerization

Group transfer polymerization allows the synthesis of block copolymers of different methacrylate or acrylate monomers, such as methyl methacrylate and allyl methacrylate [Hertler, 1996 Webster and Sogah, 1989]. The synthesis of mixed methacrylate-acrylate block copolymers requires that the less reactive monomer (methacrylate) be polymerized first. The silyl dialkylketene acetal propagating center from methacrylate polymerization is more reactive for initiation of acrylate polymerization than the silyl monoalkylketene acetal propagating center from acrylate polymerization is for initiation of methacrylate polymerization. Bifunctional initiators such as l,4-bis(methoxytri methyl si loxymethylene)cyclohexane (XXXIII) are useful for synthesizing ABA block copolymers where the middle block is methacrylate [Steinbrecht and Bandermann, 1989 Yu et al., 1988]. 

Another straightforward method to reduce the gloss consists in admixing a dull graft copolymer as dulling agent (33). Such copolymers may be prepared from n-butyl acrylate, allyl methacrylate, and hydroxypropyl methacrylate. Likewise, hydroxypropyl methacrylate may be substituted by maleic anhydride. The polymerization is started by 2,2 -azobi sisobu ty roni trile and peroxides. 

This study illustrates a particular use of FT-Raman spectroscopy (Section 2.4.2) to monitor an emulsion polymerization of an acrylic/methacrylic copolymer. There are four reaction components to an emulsion polymerization water-immiscible monomer, water, initiator, and emulsifier. During the reaction process, the monomers become solubilized by the emulsifier. Polymerization reactions were carried using three monomers BA (butyl acrylate), MMA (methyl methacrylate), and AMA (allyl methacrylate). Figure 7-1 shows the FT-Raman spectra of the pure monomers, with the strong vC=C bands highlighted at 1,650 and 1,630 cm-1. The reaction was made at 74°C. As the polymerization proceeded, the disappearance of the C=C vibration could be followed, as illustrated in Fig. 7-2, which shows a plot of the concentration of the vC=C bonds in the emulsion with reaction time. After two hours of the monomer feed, 5% of the unreacted double bonds remained. As the... 

Funk [3] prepared hydrogels with different pH values by reacting 90 parts of hydrophilic polymeric agents with glacial acrylic acid, water, and penta-erythritol triallyl with 10 parts of acrylic acid, sorbitan monococoate, and allyl methacrylate. 

Matsumoto et al. [135] studied the kinetics of the emulsion crosslinking polymerization and copolymerization of allyl methacrylate (AMA) with MMA, BMA and ethylene dimethacryllate (EDMA). 

Methacrylates containing a functional group in the ester, such as allyl methacrylate and glycidyl methacrylate, can be directly polymerized by GTP , which is advantageous because no protection of the functional group is needed prior to polymerization. 

More satisfactory data have been obtained for methyl methacrylate polymerization using soluble allylic compounds such as Cr(7r-C3115)3 or Cr(7r-2Me—C3 H4 )3 [229]. With these catalysts the rate relationship in the early stages of reaction is... 

A common feature of the emulsion polymerization of allyl methacrylate (AMA) is the slow rise to a maximal Rp and two rate regions [119]. The increase of Rp is ascribed to the increased number of latex particles, while the decrease of Rp is attributed to the decreased monomer concentration at the reaction loci. The slow accumulation of polymer in the monomer droplets (due to the very low reactivity of AMA) retards the monomer droplet degradation and the transfer of monomer from monomer droplets to the reaction loci but enhances the monomer droplet nucleation. Rp/Np increases with increasing particle size. The slight increase in Rp with increasing [SDS] is due to the high coverage of the droplet surface by SDS. 

Thiol-Ene Photopolymerization The thiol-ene polymerization of suitable systems (10.84) in film is insensitive to oxygen. The reaction refers to the addition of a thiol to a double bond (e.g., vinyl, allyl, acrylate, and methacrylate) [310] and has led in these past years to a new revival of interest [311,312]. Thiol-vinyl ether or -allyl ether polymerization shows some following interesting features very fast process, low or even no oxygen inhibition effect and formation of highly cross-linked networks with good adhesion, and physical and mechanical properties. 

Another interesting three-component LIPN consists of crosslinked polyorganosiloxane (tet-raethoxysilane as crosslinker) as the first stage, swollen by butyl acrylate monomer (allyl methacrylate as crosslinker) and then polymerized to form the second component, and finally, poly(methyl methacrylate) was grafted onto the IPN core as the shell layer [Isao et al, 1992], Such kind of LIPNs are found to be a good impact modifiers in thermoplastics i.e., they are toughened by the addition of finely divided low phase. 

Ultraviolet-Initialed Polymerization of Allyl Methacrylate with Benzoyl... 

Allyl acrylate and methacrylate are reasonably simple to synthesize. In fact, allyl methacrylate is manufactured in bulk quantities. Since each of these monomers contains two double bonds of distinctly different susceptibility to polymerization when considered individually, these monomers are interesting both from the practical as well as the theoretical standpoint. 

Blout and co-workers [70,71] studied the initiation of allyl methacrylate using biacetyl and UV radiation at low temperatures and using benzoyl peroxide at higher temperatures. At 1°C, gelation occured only after 39% conversion, whereas gelation at higher temperatures took place at 6% conversion. Data on the unsaturation of the soluble prepolymers might be used to postulate cyclization polymerizations. At the time of this work, however, this concept had not yet been established, hence this factor was not considered. 

Two possible structure of the cyclic radicals which may be involved in the polymerization of allyl methacrylate are given in Fig. 6. 

Procedure 6-1 is an example of the solution polymerization of allyl methacrylate using benzoyl peroxide as initiator. The polymer is said to be thermoplastic. 

By conventional emulsion polymerization procedures, a crosslinked copolymer of butyl acrylate and 1% allyl methacrylate was formed in the presence of methyl methacrylate. Then additional methyl methacrylate is polymerized in the system. The resultant product was a poly(methyl methacrylate) with improved... 

Copolymers containing allyl methacrylate have found application as an additive to other resin to enhance the properties of the system. For example, in one patent disclosure, an aqueous emulsion polymer was formed in water using 0.03 gm of sodium carbonate, 50 gm of methyl methacrylate, 2.0 gm of ethyl acrylate, and 0.1 gm of allyl methacrylate, and 0.40 gm of the sodium salt of an allyl Ci3-alkyl ester of sulfosuccinic acid. The polymerization was initiated with sodium persulfate and heated at 83°C for 1 hr. To this latex, 40 gm of butyl acrylate, 10 gm of styrene, 1.0 gm of allyl methacrylate, and another 0.40 gm of the above surfactant were added while polymerization continued. In a third... 

For the manufacture of a resin that is to be used for soft, water-containing contact lenses with high oxygen permeability, good mechanical strength, and heat resistance, a copolymer of 2-hydroxypropyl isopropyl fiimarate and allyl methacrylate has been the subject of a Japanese patent disclosure [80]. Presumably these polymers were formed by a bulk polymerization process. 

Procedure 6-3 illustrates the use of biacetyl as an initiator for the polymerization of allyl methacrylate at a low temperature. It should be noted that after 200 min the gel point is reached at 30% conversion. 

The UV-initiated polymerization of allyl methacrylate is carried out in a 500-ml Pyrex or Vycor Erlenmeyer flask with a side arm. The front of the flask is painted black except for an area of 4 x 11 cm which assures that a constant area is exposed to the radiation source. The back and bottom of the flask is covered with aluminum foil. The side arm is used for withdrawing samples periodically. The charged flask is kept in a stirred, water thermostat controlled to 1°C. Preparations are run under a slight positive pressure of purified nitrogen. 

Table X outlines the results of a number of polymerizations of allyl methacrylate carried out using Procedure 6-3. The reduced viscosities of the isolated polymers are given in Table X. In several cases the reduced viscosities are given for polymer samples taken as the preparation proceeded but before the gel point had been reached.

In addition, allyl methacrylate is often added to a latex formulation as a crosslinking/grafting monomer [52] especially in the case of core-shell latexes. This monomer is often used to promote adhesion between various polymeric layers, especially in multilayered composite latex particles, which are often used as impact modifiers [53]. 

National Starch Chemical Hot melt copolymer containing acrylic, allyl acrylate or methacrylate, polymerized by EB. PSA properties given. 

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