P-Chloro-styrene

DUV exposure of poly( p-substituted styrenes), such as poly( p-chloro-styrene), poly( p-chloromethylstyrene), and poly( p-hydroxystyrene) [poly(p-vinylphenol)] (structure 3.11), in air leads to photocross-linking and photooxidation. Consequently, DUV hardening is applicable to resists based on these polymers as well as novolac-based resists (168, 169). 

Poly(p-chloro styrene) Poly(oxy-2,2-dichloromethyltrimethylene) Poly(oxy-1,1 -dichloromethyltrimethylene) Poly(o-methyl styrene)... 

Young s modulus, yield (break) strength, and elongation to yield (break) have been measured for blends of poly (2,6-dimethyl-1, 4-phenylene oxide)(PPO) with polystyrene (PS), poly (p-chloro-styrene) (PpClS), and random copolymers of styrene and 2 -ch loro-styrene)(pels). The significant difference between blend compositions is the compatibility of PPO with each styrene polymer. 

In summary of the above results, PPO/poly(styrene-co-p-chloro-styrene) blends may be divided into three compatibility categories depending upon the pClS composition of the copolymer as follows ... 

One way to overcome such problems is to consider solvent(l)/polymer(2)/ polymer(3) ternary systems any method that determines either AG or its derivatives should make it possible to calculate Xi3- Thus, for example, osmotic pressure measurements were used to characterize PS/PVME blends dissolved in either toluene or ethylbenzene (Shiomi et al. 1985). The Xi3 was found to depend on the blends composition. Elimination of the solvent effects gave X23/E1 = —10 (7.41 — 11.0103). Thus, the system was expected to remain miscible up to a PVME volume fraction of 03 = 0.67. Osmotic pressure has also been used to determine X23 = 0.070 for PS with poly(p-chloro styrene) in toluene, 2-butanone, and cumene (Ogawa et al. 1986). For the same system, X23 = 0.087 was calculated from intrinsic viscosity measurements. Thus, the system is thermodynamically immiscible. More recently, osmotic pressure measurements in cyclohexanone of a ternary system resulted in X23ipoly(vinylchloride-co-vinylacetate) blends with a series of acrylic copolymers (Sato et al. 1997). 

The consistency of these various methods may be evaluated from the results listed in Table I of data obtained with polystyrene in solvents of low viscosity by the sound absorption (SA) and NMR relaxation methods, for poly(p-chloro-styrene) by dielectric dispersion (DD), for polystyrene labelled with nitroxyl by the ESR method and for a styrene copolymer with a small concentration of 9-p-vinylphenyl-lO-phenylanthracene residues by depolarization of fluorescence (DF). It may be seen that sound absorption and dielectric dispersion yield similar transition frequencies in the range of 12-35 MHz at 10-25 C,... 

Other polymers of the perpendicular dipole type so studied indude poly-(dimethyl oxane) pdy(vinyl chloride) pdystyrene pdy(p-chloro-styrene) °, and poly(p-fluorostyrene) . For vinyl polymers the stereochemistry of placements effects the dipole moment ratio, and hence tacticity is reflected by dipole moment measurements. The statistics of such systems, which are stereochemical copoljnners, can be developed in terms of a stereochemical replication probability Pr whose numerical value guides the probability of isotactic (p, 0.95),... 

A more simple alternative method to reduce diffusivity of active molecules in solid polymers and to prevent their self-aggregation consists of the formation of co-crystals with suitable polymer hosts. Polymeric co-crystalUne phases are quite common for several regular and stereoregular polymers Uke syndiotactic polystyrene (SPS) [17-24], syndiotactic poly-p-methyl-styrene [25-31], syndiotactic poly-p-chloro-styrene [32], polyethyleneoxide [33-37], poly (muconic acid) [38,39], polyoxacyclobutane [40], or syndiotactic polymethyl-... 

---