Polystyrene PS/PMMA

In this case, B (the anchor chain, in red) is chosen to be highly insoluble in the medium and has a strong affinity to the surface. Examples of B chains for hydrophobic sohds are polystyrene (PS), PMMA, PPO or alkyl chains, provided that these have several attachments to the surface. The A-stabihsing (blue) chain must be soluble in the medium and strongly solvated by its molecules. In addition. 

Brown H, Char K, Define VR, Green PE (1993) Effects of a diblock copolymer on adhesion between immiscible polymtas. 1. Polystyrene (PS)-PMMA copolymer between PS and PMMA. Macromolecules 26 4155-4163... 

It is well known that the properties and structures of the surface and interface are different from those in a bulk state. The 3D observations made using con-focal microscopy are very useful for discussing the effects of the surface/inter-face on the phase-separation structure. Kumacheva et al. studied the morphology of the surface and bulk of a polystyrene (PS)/PMMA blend prepared by casting from a toluene solution [20]. The cross-sectional image of a PS/PMMA blend is shown in Figure 19.4, where the bright areas correspond to the PMMA domains. The depth-dependent phase-separation structure was... 

Fig. 7. Glass-tiansition tempeiatuies of (A) polymetfiylinetfiaciylate (PMMA) ( ) polymetfiylinetfiaciylate-fo-styiene (SMMA60) and ( ) polystyrene (PS) as a function of carbon dioxide pressure, where the solid line represents CO2 vapor pressure (37). To convert MPa to psi, multiply by 145.

Many of the most floppy polymers have half-melted in this way at room temperature. The temperature at which this happens is called the glass temperature, Tq, for the polymer. Some polymers, which have no cross-links, melt completely at temperatures above T, becoming viscous liquids. Others, containing cross-links, become leathery (like PVC) or rubbery (as polystyrene butadiene does). Some typical values for Tg are polymethylmethacrylate (PMMA, or perspex), 100°C polystyrene (PS), 90°C polyethylene (low-density form), -20°C natural rubber, -40°C. To summarise, above Tc. the polymer is leathery, rubbery or molten below, it is a true solid with a modulus of at least 2GNm . This behaviour is shown in Fig. 6.2 which also shows how the stiffness of polymers increases as the covalent cross-link density increases, towards the value for diamond (which is simply a polymer with 100% of its bonds cross-linked. Fig. 4.7). Stiff polymers, then, are possible the stiffest now available have moduli comparable with that of aluminium. 

Pa, would deform appreciably under the action of loads comparable to the pull-off force given by Eq. 16. It is for this reason that the JKR type measurements are usually done on soft elastic materials such as crosslinked PI rubber [45,46] or crosslinked PDMS [42-44,47-50]. However glassy polymers such as polystyrene (PS) and PMMA are relatively hard, with bulk moduli of the order of 10 Pa. It can be seen from Eq. 11 that a varies as Thus, increasing K a factor of... 

The main experimental techniques used to study the failure processes at the scale of a chain have involved the use of deuterated polymers, particularly copolymers, at the interface and the measurement of the amounts of the deuterated copolymers at each of the fracture surfaces. The presence and quantity of the deuterated copolymer has typically been measured using forward recoil ion scattering (FRES) or secondary ion mass spectroscopy (SIMS). The technique was originally used in a study of the effects of placing polystyrene-polymethyl methacrylate (PS-PMMA) block copolymers of total molecular weight of 200,000 Da at an interface between polyphenylene ether (PPE or PPO) and PMMA copolymers [1]. The PS block is miscible in the PPE. The use of copolymers where just the PS block was deuterated and copolymers where just the PMMA block was deuterated showed that, when the interface was fractured, the copolymer molecules all broke close to their junction points The basic idea of this technique is shown in Fig, I. 

The soapless seeded emulsion copolymerization method was used for producing uniform microspheres prepared by the copolymerization of styrene with polar, functional monomers [115-117]. In this series, polysty-rene-polymethacrylic acid (PS/PMAAc), poly sty rene-polymethylmethacrylate-polymethacrylic acid (PS/ PMMA/PMAAc), polystyrene-polyhydroxyethylmeth-acrylate (PS/PHEMA), and polystyrene-polyacrylic acid (PS/PAAc) uniform copolymer microspheres were synthesized by applying a multistage soapless emulsion polymerization process. The composition and the average size of the uniform copolymer latices prepared by multistage soapless emulsion copolymerization are given in Table 11. 

A radical initiator based on the oxidation adduct of an alkyl-9-BBN (47) has been utilized to produce poly(methylmethacrylate) (48) (Fig. 31) from methylmethacrylate monomer by a living anionic polymerization route that does not require the mediation of a metal catalyst. The relatively broad molecular weight distribution (PDI = (MJM ) 2.5) compared with those in living anionic polymerization cases was attributed to the slow initiation of the polymerization.69 A similar radical polymerization route aided by 47 was utilized in the synthesis of functionalized syndiotactic polystyrene (PS) polymers by the copolymerization of styrene.70 The borane groups in the functionalized syndiotactic polystyrenes were transformed into free-radical initiators for the in situ free-radical graft polymerization to prepare s-PS-g-PMMA graft copolymers. 

Figure 6 (A) Non-isothermal chemiluminescence runs for oxidation of polystyrene (PS), polyethylene terephthalate) (PETP) and polyfmethyl methacrylate) (PMMA), in oxygen, heating rate 2.5°C/min. (B) Non-isothermal chemiluminescence runs for oxidation of polypropylene (PP), polyamide 6 (PA 6), poly(vinyl pyrrolidone) (PVP), polyethylene (PE) and polyamide 66 (PA 66), in oxygen, heating rate 2.5°C/min.

The multilayer film of the optical core produces a green reflector. The visual effects of the green reflector are not easily reproduced, yielding the easily identified security feature. Possible raw materials are polystyrene (PS), and polymethylmethacrylate (PMMA). There is a substantial difference in refractive... 

MALDI is the method of choice for the analysis of synthetic polymers because it usually provides solely intact and singly charged [62] quasimolecular ions over an essentially unlimited mass range. [22,23] While polar polymers such as poly(methylmethacrylate) (PMMA), [83,120] polyethylene glycol (PEG), [120,121] and others [79,122,123] readily form [M+H] or [M+alkali] ions, nonpolar polymers like polystyrene (PS) [99,100,105,106] or non-functionalized polymers like polyethylene (PE) [102,103] can only be cationized by transition metal ions in their l-t oxidation state. [99,100] The formation of evenly spaced oligomer ion series can also be employed to establish an internal mass calibration of a spectrum. [122]... 

Liu and Rauch (2003) of Motorola investigated oligonucleotide probe attachment onto polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), and polypropylene (PP) plastic surfaces. They utilized three different immobilization processes SurModics surface modification solution (that allows attachment of adsorbed reactive groups to a surface by photoactivation of polymers at 254 nm). Pierce Reactive-Bind coating solution, and CTAB (cetyltrimethylammonium bromide, a cationic detergent). Not surprisingly, the microarray performances on these plastics varied. 

The polystyrene (PS) and polymethylmethacrylate (PMMA) narrow molecular weight standards were obtained from three kits (Polymer Laboratories, S-L-10, S-M-10 and M-M-10) covering the range from 3,000,000 to 500. Five nonylphenyl-terminated polyethylene oxides (Aldrich, Igepals)... 

Recently, optical telecommunications tliat transmit large amounts of information via light signals have been rapidly replacing conventional electrical telecommunications. Optical polymers, such as poly(methylmethacrylate) (PMMA), polystyrene (PS), and polycarbonate (PC) are used for plastic optical fibers and waveguides. However, these polymers do not have enough Ihermal... 

Fig. 18. Induced open-circuit voltage in elongation plotted against amplitude at the end of film for as-cast films polypropylene (PP), high-density polyethylene (PE(H)), low-density polyethylene(PE(L)), polystyrene PS), and poly(methyl methacrylate) (PMMA). Span length = 3.6 cm. Electrode area=2.5 x 2.5 cm2. Film thickness =0.5 mm. Reproduced from Furukawa and others [J. Appl. Polym. Sci. 12, 2675 (1968)] by permission of John Wiley Sons, Inc.

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. 

Dawkins and Taylor109 dispersed poly(methyl methacrylate) (PMMA) or polystyrene (PS) particles in n-alkanes stabilized by AB block copolymers of styrene and dimethyl-siloxane. In these cases, styrene blocks act as anchors and dimethylsiloxane blocks give a surface layer. The thickness 6 of the dimethylsiloxane layer was determined by viscosity measurements as a function of the molecular weight of dimethylsiloxane blocks. 

Dopant orientation during and following electric field-induced poling can be studied continuously and in real time in order to examine the microenvironment surrounding the dopants in terms of the polymer relaxations and the applied corona field. In the results presented below, the SHG of 4-dimethylamino-4 -nitrostilbene (DANS) dispersed in polystyrene (PS) or poly(methyl methacrylate) (PMMA) matrices has been examined in corona poled films as a function of temperature in order to understand the effect of thermal conditions on the temporal stability of the dopant orientation. 

It was previously reported that the homopolymer surfactant PFOA successfully stabilized poly(methyl methacrylate) (PMMA) dispersion polymerizations (DeSimone et al., 1994 Hsiao et ah, 1995), but was not successful for styrene dispersion polymerizations (Canelas et al., 1996). In these styrene polymerizations, the C02 pressure used was 204 bar. However, later studies showed that both PFOA and poly(l,l-dihydroper-fluorooctyl methacrylate) (PFOMA) could stabilize polystyrene (PS) particles (Shiho and DeSimone, 1999) when a higher pressure was used. These polymerizations were conducted at 370 bar, 65 °C, and the particle size could be varied from 3 to 10 pm by varying the concentration of stabilizer. These homopolymer surfactants are less expensive and easier to synthesize than block copolymer surfactants and provide access to a large range of particle sizes. 

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