PMMA formula

PMI more heat-resistant and suitable for foam manufacture. 

PMMA is handicapped by a low impact resistance, limited heat behaviour (except for the acrylic imides), inherent flammability, sensitivity to environmental stress cracking in the presence of certain chemicals, chemical attack by certain current solvents. For some grades, processing can be more difficult than for some other current thermoplastics. 

They can be classified according to the type of processing, specific properties or targeted applications  

As for all plastics, the costs fluctuate widely with the crude oil price and are only given to provide a general idea. They are generally of the order of a few Euros per kilogram. 

Casting, continuous sheet casting between stainless-steel belts, pouring and several methods in the molten state are usable extrusion, injection, compression, thermoforming, co-injection, machining, welding. Specific grades of PMI can be foamed. 

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At M of the original PMMA 670K, the radius of gyration R of the polymer is estimated to be 30 nm. Here it was assumed that the SEC retention time is a function of R, and an empirical formula... 

Fig. 11 Chemical formulas of poly(acryl amide) (PAAm), poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), poly(t-butyl acrylate) (PtBA), and poly(acrylic acid) (PAA), and poly(dimethyl aminoethyl methacrylate) (PDMAEMA)...

The polymer resist exhibiting the lowest PE rate or highest etch resistance versus PMMA or oxide is poly(styrene) (see Table IV). This system, like the others of Table IV, is representative of a vinyl pol3mier with general structural formula of -(CH2-CXY)-. Poly(chlorostyrene), a chlorinated derivative of the aromatic poly(styrene), exhibits equal resistance towards all three dry etch processes. Here halogenatlon has not enhanced the etch rate or reduced the resistance as seen before for PTECM, PTFEM, and PMCA nonaromatic systems. Therefore, the aromatic side group must... 

PMMA is the polymer formed from the monomer starting material methyl methacrylic acid which has the chemical formula CH2 = C(CH3)(C02CH3). 

Methyl methacrylate (MMA) has the formula CH2 = ClCHa) (COOCH3). The vapor pressure of MMA due to its vaporization is estimated by [3] In P(Atm) = 11.79 — 4410/T(K), assuming a constant heat of vaporization. For the depolymerization reaction, the temperature which gives 1 atm of MMA (the product) is 164 C [26]. This temperature establishes the pressure equilibrium constant and therefore the Gibbs fiiee energy for the depolymerization reaction. Answer The depolymerization of PMMA rate constant given by [26] rate constant = 3.87 x 10 exp(—175 kJ/mole/RgT) gm/cm sec. 

We cannot say what the relative mix of photochemical and thermal effects is as yet. The literature suggests that significant photochemical reactions should occur due to 248nm irradiation of acridine (25,26), but these are not the massive bond-breaking type that characterize 193nm photoablation(16). The fluorescence yield of acridine in PMMA is known to be about 0.2 (26) so considerable heat is produced by the absorption of short pulses in the 100 mJ/cm2 range an estimate based on an approximate heat capacity formula (27) is about 300 0. The excited state properties of acridine in PMMA show a pronounced temperature dependence (26). It seems likely that the bleaching arises from a combination of photochemical destruction of the acridine chromophore and polymer ablation. 

For polystyrene (benzene solution) we used a diagram of Marzolph and Schulz (22). The values for PMMA (solvent CHCI3) were obtained with the formula (7)... 

Poly(acrylates) and poly(methacrylates) form another class of common polymers with saturated carbon chain backbone. Polyacrylates can be considered vinyl polymers with the -COOR group attached at every other carbon atom in the chain. However, due to their common use and particular properties, polyacrylates form a separate polymer class together with polymethacrylates. Among the most common polymers from this class are those obtained from acrylic acid methyl ester (PMA) and methylacrylic (methacrylic) acid methyl ester (PMMA). Acrylic polymers have many practical applications in automotive industry, in the production of medical materials, paints, coatings and lacquers, adhesives, textiles, and synthetic leather. Poly(methacrylic acid methyl ester) can be obtained in cast sheets with applications in technical components, furniture, building materials, etc. Formulas for poly(acrylic acid), two polyacrylates, and poly(methyl methacrylate) are shown below ... 

The authors [105] used amorphous glassy polymers PMMA, polycarbonate (PC) and polyarylate (PAr). The necessary for further evaluations shear modulus values G were obtained according to Young s modulus E experimental values with the formula using [88] ... 

The appearance of a maximum in the chain length dependence of the characteristic ratio was first found by Yoon and Flory [60] in the RIS chain computations on atactic and syndiotactic polyfmethyl methacrylate)(PMMA). Yamakawa and Fujii [63] showed that their formula for the HW chain with <7o can be fitted accurately to the computed results of Yoon and Flory over dm almost entire range of chain length if the basic parameters of the HW chain are suitably chosen. A similar agreement in characteristic ratio between the HW (<7o = 0) and RIS chains was obtained for other flexible polymers. The choice of relation between the RIS chain model and the discrete chain whose continuous limit is the HW chain. 

PMMA is characterized by crystal clear transparency, unexcelled weatherability, and a useful combination of stiffness, density, and moderate toughness. The heat deflection temperatures range from 165 to 212° F, with a service temperature of 200° F. Improvement of the mechanical properties of PMMA can be achieved by orientation of heat-cast sheets. The structural formula for PMMA is as follows ... 

Figure 4.13. The interfacial tension between polyst5n-ene and poly(methyl methacrylate). The relative molecular mass of the PMMA was 10000 and the temperature of measurement was 199 °C. The solid line is the prediction of the Broseta equation (Broseta et al. 1990) with x = 0.045. The dashed line is the prediction of the Broseta equation with the coefficient changed from n /6 to 1.35, to bring it into line with the Freed interpolation formula (Tang and Freed 1991), equation (4.3.17), with x = 0.055. Data from Anastasiadis et al. (1988).

Manned et al. assumed that the volume of the tube remains constant by deformation, and derived a result which has the same time dependence as eqn (7.122) but different strain dependence. Though an experiment on PMMA seems to fit with the modified formula, caution is needed in accepting the modification since critical experiments need... 

The negative ion spectrum of PMMA is shown in Figure 15. With the absence of hydrocarbon noise this is a much simpler spectrum and the pattern of peaks clearly reflects the repeat unit mass of 100 amu. Negative ion peaks characteristic of all methacrylates, because the side-chain alkyl group (R) has been lost, are at mJz 85,109,125, and 139. Specific ions having one or more intact side chains have the generic formulae [M-l-55], [2M-15], [2M-I-41], [2M-I-55] , and [3M-15] ,... 

Rheological behaviour of the TPVs that were prepared from dynamic vulcanization of NR-g-PMMA and PMMA blends using various vulcanization systems including conventional vulcanization (CV) and efficient sulphur vulcanization (EV) systems were studied by Nakason et al The ingredient formulas of each vulcanization systems are summarized in Table 18.6. 

Poly(methacrylates) are polymers of the esters of methacrylic acids. The most commonly used among them is poly(methyl methacrylate) (PMMA). Poly(methyl methacrylate) or poly(methyl 2-methylpropenoate) is the polymer of methyl methacrylate, with chemical formula It is a clear, colorless polymer available on the market... 

Hsu et al. [213] have explored the potential of LD-FIMS for the simultaneous detection and identification of polymer and dye components of commercial solid polymeric materials. It was shown that LD-FTMS in LD/EI mode can detect and identily (by chemical formula) dyes in solid PMMA at concentrations at least an order of magnitude lower (0.1 vs. 1-2 wt.%) than those obtained by the best currently available alternative method (ATR-ETIR). The chemical formula of each dye could be established by accurate (0.5-20 ppm) mass measurement (calcd./measd. mass of l-(methylamino)anthraqui-none 238.0862 and 238.0816 Da, respectively). LD-FTMS thus offers a sensitive and accurate means for identifying dyes in solid polymers (cfr. Fig. 3.11). 

The curves of dependence of the relative free energy of PS and PMMA filled with glass powder on the effective thickness of the interlayer between two filler particles are given in Figure 3.4. The values AF/ kT were calculated according to the formula ... 

The width of the adsorbed polymer layer is also consistent with the chain radius of gyration which can be calculated using the well-known formula Rf = a(V7). Taking N 1200 and a = 2.52 A for the PMMA chain, we obtain Rq = 173 A. If the profile is assumed to be a step function of width Rq one than expects < z > = Rq/ = 86 A which is very close to our experimental finding of 73 8 A. 

It is demonstrated that the above technique can detect and identify (by chemical formulae) dyes in solid PMMA commercial plastics at concentrations at least on order of magnitude lower (0.1% vs l-2wt%) than those obtained by the best currently-available alternative method (ATR Fourier transform IR spectrometry). Both untreated and redissolved PMMA can be characterised, in the presence and absence of up to three dyes in a single sample. 44 refs. USA... 

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