Methyl methacrylate, deuterated

The same type of addition—as shown by X-ray analysis—occurs in the cationic polymerization of alkenyl ethers R—CH=CH—OR and of 8-chlorovinyl ethers (395). However, NMR analysis showed the presence of some configurational disorder (396). The stereochemistry of acrylate polymerization, determined by the use of deuterated monomers, was found to be strongly dependent on the reaction environment and, in particular, on the solvation of the growing-chain-catalyst system at both the a and jS carbon atoms (390, 397-399). Non-solvated contact ion pairs such as those existing in the presence of lithium catalysts in toluene at low temperature, are responsible for the formation of threo isotactic sequences from cis monomers and, therefore, involve a trans addition in contrast, solvent separated ion pairs (fluorenyllithium in THF) give rise to a predominantly syndiotactic polymer. Finally, in mixed ether-hydrocarbon solvents where there are probably peripherally solvated ion pairs, a predominantly isotactic polymer with nonconstant stereochemistry in the jS position is obtained. It seems evident fiom this complexity of situations that the micro-tacticity of anionic poly(methyl methacrylate) cannot be interpreted by a simple Bernoulli distribution, as has already been discussed in Sect. III-A. 

Nuclear Magnetic Resonance (NMR) - NMR spectra of cellulose nitrate-g-poly(methyl methacrylate) and cellulose nitrate were recorded in deuterated acetone using Perkin-Elmer-R-32 (90 MHz). 

Using poly (methyl methacrylate), PMMA, perdeuterated PMMA, and polystyrene, it was found that absorptive losses are very low (<0.1 dB/cm) at wavelengths between 0.5 and 1.0 m, and that losses due to C-H overtones can be made lower than 0.1 dB/cm between 1 and 2 m by deuteration. ... 

The polymerization mechanism is based on the insertion of a coordinated monomer into a covalent Mg C bond, as in methyl methacrylate. However, different modes of monomer double-bound opening cis, trans, and the 1 1 cis trans mixture) can occur, depending on the polymerization conditions and on the monomer [59]. Several mechanistic studies were performed using partially deuterated monomers, such as methyl a,) ,i/2-acrylate E and Z isomers) [60], or (Z)-ethyl a-methyl-)5-Ji-acrylate [61]. 

For all these specialty polymers, deuterium can be used as a label on one or the other monomer. Deuterium labeling allows the use of techniques based on ion detection such as forward recoil spectrometry (FRES), nuclear reaction analysis (NRA) or secondary ion mass spectrometry (SIMS). If a high-resolution depth profile of the interfacial region is needed, neutron reflectivity can also be used. The main drawback of that approach is the cost of the deuterated polymers while deuterated styrene and methyl methacrylate are expensive but commercially available, other monomers need to be synthesized and the cost can be quite prohibitive. 

Another type of dependence of effective interfacial width wD on film thickness D was observed [130] for immiscible mixture of deuterated polystyrene (dPS) and poly(methyl methacrylate) (PMMA) (at T TC) an increase, from wd=1.8(4) nm for a dPS layer thickness D=6 nm to wd(D=100 nm)=2.5(4) nm, follows the logarithmic dependence wD°clnD (intrinsic interfacial width w= 1.5 nm). This may reflect [6,224] long range forces acting from the external interfaces on the internal interface Ie(x,y). On the contrary, the relation wd D1/2 found for random olefines [121] corresponds [6,224] to short range forces. We note also that capillary waves in dPS/PMMA system were observed [130] already for the thickness-to-intrinsic width ratio D/w<85 ... 

Copolymer compositions were determined by a high resolution nuclear magnetic resonance spectrometer (180 HMz). Copolymers of methyl methacrylate and styrene were dissolved in deuterated chloroform for the analysis. Deuterated pyridine was the solvent for the methyl methacrylate - methacrylic acid copolymers. Elemental analysis was also used in copolymer composition analysis to complement the NMR data. 

Figure 3. NMR spectra of poly(methyl methacrylate-co-methacrylic acid) obtained by (1) plasma-initiated polymerization and (2) thermal polymerization in 0.2% deuterated pyridine.

Figures 3.7 and 3.8 shows the frequency dependencies of Ti and NOE measured for the CH2 (rrr) carbon of poly(methyl methacrylate) (PMMA) in a deuterated chloroform solution at 55°C [10]. Different curves indicate the simulated results obtained by using the box-type distribution, log- distribution, 2r and 3t models described above. As is clearly seen in Fig.

Table 11. Polymerization rate and elementary rate constants in the free radical polymerization of methyl methacrylate and vinyl acetate in benzene and deuterated benzene at 30 °C17 ...

Figure 7.16 shows the neutron reflectivity determined by Anastasiadis et al.15 with a sample in which a thin film of a diblock copolymer was deposited on a silicon substrate. The diblock copolymer, of molecular weight 100,000, consists of a block of deuterated polystyrene joined to a block of hydrogenous poly(methyl methacrylate) of about equal length and is therefore expected to organize itself into a lamellar... 

Atactic poly(methyl methacrylate) Atactic polystyrene Butyl-rubber Chlorinated polyethylene Deuterated high density polyethylene Ethylene butylacrylate Elastomeric copolymer from ethylene and ethyl acrylate Elastomeric terpolymer from ethylene, propylene and a non-conjugated diene Elastomeric ethylene-propylene... 

SUN Sun, S.F., Light scattering studies of deuterated polystyrene-poly(methyl methacrylate) diblock copolymers in 1,4-dioxane solutions, Makromol. Chem., Rapid Commun., 4,203,1983. 

FIGURE 10.10 Intensity vs. Q plot of SANS data for various concentrations c of hydrogenous poly (methyl methacrylate) (PMMA) dissolved in deuterated PMMA. (From Kirste et al., Polymer 16, 120, 1975. With permission.)... 

H NMR spectra were recorded on Briiker ACP 400 or DPX 400 spectrometers using deuterated solvents obtained from CEA or Aldrich. Polymerization kinetics, followed by NMR, were recorded using the Briiker built-in kinetics software. Molecular mass analyses were carried out by gel permeation (size exclusion) chromatography on a Polymer Laboratories system. THF was the eluent at 1.0 mL min with a PL-gel 5 jim (50 X 7.5 mm) guard column, two PL-gel 5 pm (300 x 7.5 mm) mixed-C columns with a refractive index detector. Samples were compared against narrow standards of poly(methyl methacrylate), A/p = 200 to 1.577 x 10 g mol , obtained from Polymer Laboratories, except for methyl methacrylate dimer, trimer, and tetramer which were prepared by catalytic chain transfer polymerization at the University of Warwick. 

Figure 4.15. The interfacial width between a thin deuterated polystyrene film and poly(methyl methacrylate), measured by neutron reflectometry. The d-PS relative molecular masses were 244 000 (+), 387 000 ( ), 641 000 ( ) and 400 000 (O and A) and the PMMA relative molecular masses were 365 000 (+, , and O) and 333 000 (A). After Sferrazza et al. (1997).

Notes The values of A, B, and C and thus of y are based on a reference volume Vre/ = 0.1 nm Polymer notation A d- label preceding the polymer acronym indicates a per-deuterated polymer partially deuterated polymers are labeled as dy, df, etc., for selective deuteration of 3, 4, etc., hydrogens. Numbers in subscripted parentheses after the polymer name indicate the primary comonomer fraction, e.g., SPB(6s) is a saturated polybutadiene with 66 mol% butadiene Polymer acronyms P2VP poly(2-vinyl pyridine), P4MS poly(4-methylstyrene), PBMA poly(n-butyl methacrylate), PCHA poly(cyclohexyl acrylate), PEB poly(ethyl butylene), PIB polyisobutylene, PI polyisoprene, PMMA poly(methyl methacrylate), PPMA poly(n-pentyl methacrylate), PP polypropylene, HHPP head-to-head polypropylene, PS polystyrene, PVME poly(vinyl methyl ether), PXE poly(2,6-dimethyl-l,4-phenylene oxide), SPB saturated polybutadiene, SPI saturated polyisoprene... 

Han and Mozer have combined SANS with light scattering to evaluate the configuration of a styrene-methyl methacrylate diblock copolymer when dissolved in toluene. Here again the styrene block was fully deuterated and SANS experiments were made in deuterated toluene thereby providing the radius of gyration of the methyl methacrylate block, since the deuteropolystyrene has essentially zero contrast... 

Styrene-methyl methacrylate diblock copolymers have also been studied in a selective solvent, i.e. a solvent which is thermodynamically better for one or other block. For these experiments, p-xylene was used as the solvent since it had been previously reported as a theta solvent for polymethyl methacrylate at drca 40 °C. Separate SANS measurements were made on a copolymer with a deuterated styrene block dissolved in deuterated xylene and in hydrogenous xylene at tmperatures of 30 °C and 40 °C. Deutero xylene has the same scattering length density as deuterostyrene, consequently the scattered intensity is solely attributable to the methyl methacrylate block when the copolymer is dissolved in this solvent. At the two temperatures used conventional Zimm plots were obtained, however the methyl methacrylate block molecular weight obtained at 30 °C was twice that at 40 °C indicating the formation of a bimolecular multimer at 30 °C. From the radii of gyration obtained at both temperatures it appears that the methyl methacrylate block in the multimer... 

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