Styrene 2-hydroxyethyl methacrylate

Fig. 8. R/Platelet in individual platelets adhering to polymer surfaces. HSB data were statistically confirmed to be different from PSt (P < 0.5), HSR (P < 0.5) and PHEMA (P < 0.5) after 40 s R/Platelet (an index of cytoplasmic free calcium concentration) is the ratio of fluorescence emission intensitie of a Ca2 + indicator dye (Fura 2) loaded in platelets when they are excited at 340 nm and 380 nm. (Reproduced from J Biomed Mater Res [Ref 84 Prevention of changes in platelet cytoplasmic free calcium levels by interaction with 2-hydroxyethyl methacrylate/styrene block copolymer surfaces] through the courtesy of John Wiley Sons, Inc.)...

The dimethylene spiro orthocarbonate I was shown to copolymerize with a variety of monomers, including methyl methacrylate, hydroxyethyl methacrylate, styrene and diallyl carbonate. With methyl methacrylate I was shown to be less... 

Figure 14 The reversibilities of insulin permeation through polymer membranes in a two-compartment diffusion cell AH20 ( ), AS 15 (A), AS20 ( ), H ( ). Numbers indicate the content of styrene or HEMA in feed compositions in moles. H represents a cross-linked poly(2-hydroxyethyl methacrylate) (HEMA). (From Ref. 34.)... 

Polymeric particles can be constructed from a number of different monomers or copolymer combinations. Some of the more common ones include polystyrene (traditional latex particles), poly(styrene/divinylbenzene) copolymers, poly(styrene/acrylate) copolymers, polymethylmethacrylate (PMMA), poly(hydroxyethyl methacrylate) (pHEMA), poly(vinyltoluene), poly(styrene/butadiene) copolymers, and poly(styrene/vinyltoluene) copolymers. In addition, by mixing into the polymerization reaction combinations of functional monomers, one can create reactive or functional groups on the particle surface for subsequent coupling to affinity ligands. One example of this is a poly(styrene/acrylate) copolymer particle, which creates carboxylate groups within the polymer structure, the number of which is dependent on the ratio of monomers used in the polymerization process. 

The chain transfer reaction played an important role, particularly because of abstraction of the active hydrogen at a-carbon from the allyl group. Moreover, unreacted double bonds were present in the copolymer obtained. The influence of chain transfer reaction could be diminished by applying multimonomers which do not contain allyl groups. This was shown in the example of copolymerization of multimethacrylate prepared by esterification of poly(2-hydroxyethyl methacrylate) with methacryloyl chloride. Copolymerization of the multimethacrylate with vinyl monomers such as styrene or acrylonitrile can be represented by the reaction ... 

A series of polymine-graft copolymers of styrene [92-95] and hydroxyethyl methacrylate [96-98] were found to form a microdomain structure and exhibit unique biomedical behavior at the interface with living cells, such as blood platelets and lymphocytes. The most intensive studies were made with poly(hydroxyethyl methacryIate)-0ra/t-polyamine copolymers (HA) ... 

A major advantage of RAFT is that it is compatible with a wide range of monomers, including functional monomers containing, for example, acids (e.g. acrylic acid), acid salts (e.g. sodium salt of styrene sulfonic acid), hydroxyl (e.g. hydroxyethyl methacrylate) or tertiary amino (e.g. dimethylaminoethyl methacrylate). It can be used over a broad range of reaction conditions and provides in each case controlled molecular weight polymers with very narrow polydispersion. 

The internal cross-linking of styrene copolymers is dealt with in the chapter of R. N. Haward, B. M. Parker and E. F. T. White, who prepared a copolymer of styrene and hydroxyethyl methacrylate and crosslinked the copolymer with hexamethylene diisocyanate. 

Materials. Styrene-hydroxyethyl methacrylate copolymers were prepared and characterized as described in the Appendix. The copolymers used in this work contained 0.7,2.2,3.8, and 9.5 mole % HEMA. 

Figure 1. Variation in specific viscosity of a toluene solution of a styrene-hydroxyethyl methacrylate copolymer (2.2 mole % HEM A) on reaction with hexamethylene diisocyanate at 80°C. Polymer concentration 0.047%, (gram/dl.) [NCO] 0 [OH] 0 = 9.5...

With the styrene-hydroxyethyl methacrylate copolymers some deposition of polymer on the walls of the reaction vessel was generally observed after 7-8 days of reaction. It was difficult to estimate the amount of gel, but in no case was the amount found as much as 4% of the total polymer. Thus, the effect of polymer loss on intrinsic viscosity was small. 

Figure 4. Comparison of viscosity changes on reaction between styrene-hydroxyethyl methacrylate copolymer (2.2 mole % HEMA) and butyl isocyanate ( ) and hexamethylene diisocyanate (O) in toluene at 80°C.

For the styrene-hydroxyethyl methacrylate copolymers, the situation is more complex. To try to determine the nature of the reaction with... 

Figure 10. Change in viscosity over long times during reaction between styrene-hydroxyethyl methacrylate copolymer and hexamethylene diisocyanate in toluene at 80° C. Curves 1-4 (copolymer 0.7 mole % HEM A, 0.134% (gram/dl.) solution) had [NCO] 0 [O//] 0 = 102, 1.5 X 102, 10s, and 10u, respectively. Curve 5 (copolymer 2.2 mole % HEM A, 0.047% (gram/dl.) solution) had [IVCO]0 [OH]0 = 10. All solutions have approximately the same [OH]0...

Figure 12. Intrinsic viscosity change at 25°C. and specific viscosity change at 80°C. for styrene-hydroxyethyl methacrylate copolymers, 0.7 mole % HEM A (%) and 2.2 mole % HEM A (O)...

Table I. Light Scattering for Styrene—Hydroxyethyl Methacrylate Copolymer (3.8 mole % HEM A) before and after Crosslinking with Hexamethylene Diisocyanate...

To study the internal crosslinking of styrene-hydroxy ethyl methacrylate copolymers, it was necessary to prepare a range of well characterized materials containing only low concentrations of hydroxyethyl methacrylate. To ensure that the copolymers were of uniform composition, only low monomer conversions were used so that the composition of the monomer mixtures did not change appreciably during the reaction. Low polymerization temperatures were used to obtain high molecular weight copolymers. 

Table A. Composition of Styrene—Hydroxyethyl Methacrylate Copolymers Determined by Chemical Analysis...

The monomer reactivity ratios could be calculated from Table A and other values by the method of Fineman and Ross (10), but owing to the narrow range of compositions studied only the value of r2 (referring to the styrene radical) was significant. A value of 0.7 was obtained which may be compared with 0.52 for styrene-methyl methacrylate, and a value of 0.41 calculated from the Q — e values for hydroxyethyl methacrylate supplied by Rohm and Haas (25). 

Table B. Intrinsic Viscosities of Styrene—Hydroxyethyl Methacrylate Copolymers in Polar and Nonpolar Solvents...

We therefore conclude that the styrene-hydroxyethyl methacrylate copolymers used in this work have a relatively. broad molecular weight distribution and that the effect of increasing hydroxyl content on the properties of dilute toluene solution is to contract the polymer molecule and decrease the polymer-solvent interaction without causing appreciable aggregation by intermolecular hydrogen bonding. 

AA acac alt AIBN Ar Bd Bu BuA BuMA BzMA CMSty CR CT CTFE DBP DPn EA HEA HEMA HFP acrylamide acetylacetonate alternating azobisisobutyronitrile aromatic group butadiene n-butyl n-butyl acrylate n-butyl methacrylate benzyl methacrylate chloromethyl styrene counter-radical transfer constant chlorotrifluoroethylene dibenzoyl peroxide average degree of polymerization in number ethyl acrylate 2-hydroxyethyl acrylate 2-hydroxyethyl methacrylate hexafluoropropene... 

Most research into the study of dispersion polymerization involves common vinyl monomers such as styrene, (meth)acrylates, and their copolymers with stabilizers like polyvinylpyrrolidone (PVP) [33-40], poly(acrylic acid) (PAA) [18,41],poly(methacrylicacid) [42],or hydroxypropylcellulose (HPC) [43,44] in polar media (usually alcohols). However, dispersion polymerization is also used widely to prepare functional microspheres in different media [45, 46]. Some recent examples of these preparations include the (co-)polymerization of 2-hydroxyethyl methacrylate (HEMA) [47,48],4-vinylpyridine (4VP) [49], glycidyl methacrylate (GMA) [50-53], acrylamide (AAm) [54, 55], chloro-methylstyrene (CMS) [56, 57], vinylpyrrolidone (VPy) [58], Boc-p-amino-styrene (Boc-AMST) [59],andAT-vinylcarbazole (NVC) [60] (Table 1). Dispersion polymerization is usually carried out in organic liquids such as alcohols and cyclohexane, or mixed solvent-nonsolvents such as 2-butanol-toluene, alcohol-toluene, DMF-toluene, DMF-methanol, and ethanol-DMSO. In addition to conventional PVP, PAA, and PHC as dispersant, poly(vinyl methyl ether) (PVME) [54], partially hydrolyzed poly(vinyl alcohol) (hydrolysis=35%) [61], and poly(2-(dimethylamino)ethyl methacrylate-fo-butyl methacrylate)... 

The pure bulk-phase behavior was studied on blends consisting of poly(acryhc acidj/hydroxypropyl cellulose [44], poly(2-vinylpyridine)/end-sufonic acid poly(styrene) [45], and poly(acryHc acid)/poly(N,N-dimethyl-acrylamide) [46]. Goh et al. [47,48] and others [49] have studied an interesting example of [60]fullerenated poly(2-hydroxyethyl methacrylate) with poly(l-vinylimidazole) or poly(4-vinylpyridine) or poly(styrene-co-4-... 

Copolymer with styrene and 1,4-divinylbenzene, 10% alkaloid incorporation, 20% crosslinking. d Copolymer with hydroxyethyl methacrylate and ethylene glycol dimcthacrylate, 10% alkaloid incorporation, 20% crosslinking. 

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