Poly methylmethacrylate PMMA Blends

The conductivity (o-dc) of the unblended polyaniline (PAni), PAni-poly(methylmethacrylate) (PMMA) blends and the PAni extracted from blend was measured from room temperature down to millikelvin temperatures at various fields. For PAni (33%)—PMMA (67%), PAni (40%)—PMMA (60%) blends, the reduced activation energy, W = dln(o-)/dln( T), decreases on decreasing the temperature below 1 K and the systems are found to be on the metallic side of the MI transition [25a]. In the case of PAni extracted from the blend, the slope change of Woccurs at 70 K. For unblended PAni, Wincreases as temperature decreases (Figure 1.43). The temperature dependence of the conductivity is given by... 

Poly(methylmethacrylate), (PMMA), is one resist which is especially favored by researchers due to its high resolution and contrast. Linewidths as small as 100 A have been produced with an extremely high dose of x-rays (10 J/cm ) using PMMA. However, even PMMA s normal sensitivity of 600-1000 mJ/cnr is too slow for commercial use. There have been many attempts to improve the sensitivity of PMMA to electron beam irradiation mainly by copolymerization (8). In the current paper, we describe an alternative approach whereby a sensitive polymer is physically blended with PMMA to increase its sensitivity and yet maintain the good film qualities associated with PMMA as a positive x-ray resist. 

In the range of frequencies low enough that the interfacial terms become important, one can usually assume that both components of the blend are in their terminal regimes, and thus behave as Newtonian liquids. Following this reasoning, Gramespacher and Meissner (1992) divided the linear viscoelastic response of a blend of polystyrene (PS) and poly(methylmethacrylate) (PMMA) into bulk and interfacial terms, as in Eq. (9-35). The interfacial contributions were taken from the Choi-Schowalter theory for Newtonian liquids. Eq. f9-37h with ju, T], and Xj from Table 9-1. while the bulk contributions were obtained from Eq. (9-41), With these expressions for G ui and Gramespacher and... 

The interactions between two polymers could limit the free-radical decay after irradiation. Miklesova and Szocs carried out y-irradiation of miscible poly(methylmethacrylate) (PMMA)/polyefhyleneoxyde (PEO) blends at liquid N2 temperature with a total dose of 10 kGy The blends were prepared by mixing on a Brabender plasticorder during 6 or 12 min. The authors observed that the free-radical decay is slower when fhe fime of mixing is longer because the transfer of the radical center is controlled by molecular motions. These motions are affected when more interactions occur between both polymers and consequently the decay is slowed. 

Poly methylmethacrylate (PMMA) can interact with graphene sheets by the interaction of delocalized n-bonds of graphene with n-bonds of PMMA. On the other hand, as reported in articles, PVDF/PMMA blend is a miscible system. Consequently, in attempt to achieve a homogenous dispersion of nanographene layers in PVDF matrix, the use of PMMA chains as a compatiblizer can be useful. 

Construct the phase diagram for a poly(methylmethacrylate) (PMMA) and styrene acrylonitrile (SAN) blend. Use the binary interaction parameter values tabulated in Chapter 3, and use the Sanchez and Lacombe free volume theory as the equation of state. 

The miscibility and molecular dynamics of different amorphous blend systems, such as poly(methylmethacrylate) (PMMA)/polystyrene (PS), polyisoprene (PI)/... 

R., and McEwan, I. (2001) Enthalpy relaxation of styrene-maleic anhydride (SMA) copolymers. 2. Blends with poly (methylmethacrylate) (PMMA). Polymer,... 

Yb(TPP)Tp] was blended with the polymers poly (methylmethacrylate), poly(Y-butylmethacrylate), and with poly(bisphenol-A-carbonate). Near-IR emitting polymeric light-emitting diodes (PLEDs) were fabricated by spin-coating of films of the [Yb(TPP)Tp]/polymer blends on ITO glass substrates. The best device characteristics concerning the near-IR irradiance and EL efficiency was obtained for the [Yb(TPP)Tp]/PMMA blend. Flexible PLEDs can be fabricated from the [Yb(TPP)Tp]/PBMA blend.214... 

Similar behaviour has also been observed in the case of poly(caprolactone)/poly(vinyl chloride) blends and poly(vinyli-dene fluoride)/poly(methylmethacrylate) blends. These results clearly suggest that during crystallization PMMA is incorporated in the interlamellar regions of PEG spherulites. 

An excellent example of the capabilities of this technique was provided by Mokarian-Tabari et al. [167], who investigated the phase separation of immisdble polymers during spin coating from a common solvent. The FRES technique, combined with NRA, was used for a quantitative analysis of the polymer blend films prepared from a solution of polystyrene (d-PS) and poly(methylmethacrylate) (h-PMMA). The data obtained showed an evident stratification in the film, with a segregation of d-PS to the surface and an increase in PMMA content with distance from the surface (see Figure 23.37). 

Poly(2,6-dimethyl-p-phenylene ether) (PPE) was rarely blended with acrylics, viz. with styrene-methylmethacrylate-co-CW-polyisoprene [Abolins and Reinhardt, 1976] PMMA [Izawa and Nakanishi, 1973 Matsunaga et al., 1974],... 

Non-compatibilized blends of PS with either PEST or PEST and PMMA have been used for decorative applications or as the so-called plastic paper (Kamata et al. 1980). Similarly, PAr blends with either SAN (Brandstetter et al. 1983a, b, c) or high-performance blends of LCP with thermoplastic polymers (e.g., PP, PS, PC, PI) (Haghighat et al. 1992) showed adequate performance for the envisaged applications. However, most PS blends with engineering resins require compatibi-lization. Thus, for example, PS with PA-6 was compatibilized by addition of either methylmethacrylate-styrene copolymer (SMM) (Fayt et al. 1986b) or SMA (e.g., used in PARA/PS blends) (Lee and Char 1994). POM was blended with a small amount of either PS poly(a-methyl styrene) (MPS) or SAN and with particulate fillers (Tajima et al. 1991). PAr/PS blends were compatibilized with PAr-PS segmented copolymer (Unitika Ltd. 1983). 

Various workers have discussed aspects other than those mentioned above in studies of the viscoelastic properties of polymers. These include PVOH [62], hydroxy-terminated polybutadiene [63], styrene-butadiene and neoprene-type blends [64], and polyamidoimides [65]. Other aspects of viscoelasticity that have been studied include relaxation phenomena in PP [66] and methylmethacrylate-N-methyl glutarimide copolymers [67], shear flow of high-density polyethylene [68], Tg of PMMA and its copolymers with N-substituted maleimide [69] and ethylene-vinyl acetate copolymers [70], and creep behaviour of poly(p-phenylene terephthalate) [71] and PE [72]. 

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