Polyethyl methacrylate

Polyethyl Methacrylate. See under Ethyl Methacrylate in Vol 6, E308... 

Eq. (5) in conjunction with Eqs. (8) and (9) have, so far, provided adequate representation of experimental isotherms6 32, which are characterized by an initial con vex-upward portion but tend to become linear at high pressures. Values of K, K2 and s0 have been deduced by appropriate curve-fitting procedures for a wide variety of polymer-gas systems. Among the polymers involved in recent studies of this kind, one may cite polyethylene terephthalate (PET) l2 I4), polycarbonate (PC) 19 22,27), a polyimide l6,17), polymethyl and polyethyl methacrylates (PMMA and PEMA)l8), polyacrylonitrile (PAN)15), a copolyester 26), a polysulphone 23), polyphenylene oxide (PPO)25), polystyrene (PS) 27 28), polyvinyl acetate 29) and chloride 32) (PVAc and PVC), ethyl cellulose 24) (EC) and cellulose acetate (CA) 30,3I>. A considerable number of gases have been used as penetrants, notably He, Ar, N2, C02, S02 and light hydrocarbons. 

Lemos (20) (RSEARCH) 2003 BX Velocity Polyethyl methacrylate Human coronary art (Acute coronary syndromes) Sirolimus 1,4ng/mm2 Bare No... 

Schampaert (142) (C-S1R1US) 2004 BX Velocity Polyethyl methacrylate Human coronary art (long lesion, small art) Sirolimus 1,4 xg/mm2 Bare Yes... 

C 12 — and R. J. Samuels Polyethyl methacrylate. II. Dilute solution properties by viscosity and light scattering. J. Polymer Sci. 19, 463 (1956). 

Kato et al. (92) irradiated polymethylmethacrylate at -196° C under vacuum, and the spectrum shown in Fig. 16 was obtained. This spectrum was identified as due to the free radicals, COOCH3, CHO, and -CH3, which show the singlet, doublet and quartet, respectively. The half-life of methyl radicals at — 196° C was about 5 hr. It is likely that the methyl radicals are produced by the photolysis of ester side groups, just as ethyl radicals are produced after irradiation of polyethyl-methacrylate at —196° C. 

Figure 13.28 Shear modulus (a) and damping (b) at 1 Hz as a function of temperature for poly(n-alkyl methacrylate). (---) Polymethyl methacrylate (-) polyethyl methacrylate (----) poly(n-propyl meth-...

Polyethyl methacrylate (PEMA) Styrene-mediyl methacrylate [86] [51] ... 

Polyacrylate esters Polymethyl methacrylate Polyethyl methacrylate... 

Several polymers degrade primarily by a free radical depolymerisation, including polystyrene (PS) and polymethacrylates. When a free radical is produced in the backbone of polyethyl methacrylate, for example, the molecule undergoes scission to produce an unsaturated small molecule (ethyl methacrylate) and another terminal free radical. This radical will also cleave to form ethyl methacrylate and propagate the free radical. The net effect is often referred to as unzipping the polymer. 

Polyethyl methacrylate unzips extensively when heated to 600 °C for ten seconds. Copolymers of two or more methacrylate monomers will undergo the same degradation mechanism, producing a peak for each of the monomers used in the original polymerisation. 

Other applications include the fractionation of high molecular weight Ryaluronan [19], methyl methacrylate, -butyl acrylate, styrene, and maleic anhydride copolymers [20,21], partially crosslinked polyethylenes (PE) [22], star PS [23], high-density polyethylene [24], polyglycerols [25], and stereoregular polyethyl methacrylate [26]. 

Figure 9.1 Temperature dependence of loss modulus G2 for polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), poly-n-propyl methacrylate (P-n-PMA) and poly-n-butyl methacrylate (P-n-BMA). (Reproduced with permission from Heijboer, in The Physics of Non-crystalline Solids, North-Holland, Amsterdam, 1965, p. 231)...

A self-curing system based on polyethyl methacrylate(PEM) and tetrahydrofurfuryl methacrylate(THFM) was used with chlorhexidine diacetate(CX) added at levels between 0 and 12% w/w. Water uptake by the device was assessed gravimetrically and CX release measured by UV spectroscopy. Anti-... 

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