2-Hydroxy-ethyl methacrylate HEMA

Polymerizable vinyl groups can be introduced into PI precursors by treating dianhydrides with vinyl containing alcohols, such as 2-hydroxy-ethyl methacrylate (HEMA), converting into the acyl chloride and condensing with diamines, e.g., DBA. The reaction scheme is shown in Figure 15.8. 

Since the first rigid and soft CLs (SCLs) based on methyl methacrylate (MMA) and 2-hydroxy-ethyl methacrylate (HEMA) that appeared in 1936 and 1954, respectively, - a plethora of monomers has been synthesized for preparing CLs searching for adequate optical and mechanical features, low density, enough oxygen permeability, and more recently anti-biofouling properties. - ... 

Oligomer urethane acrylate (LR 8739) and photoinitiator Irgacure 184 were obtained from IAEA. Reaction diluents 2-methoxy ethyl acrylate (MEA, Tg = -110°C), 2-ethylhexyl acrylate (EHA, Tg = -50°C), 2-hydroxy ethyl methacrylate (HEMA, Tg = 55°C), N-vinyl pyrrolidone (NVP, Tg = 175°C), tripropylene glycol diacrylate (TPGDA, Tg = 90°C), and trimethylol propane triacrylate (TMPTA, Tg 250°C) were used as procured from E, Merck without any further purification. 

Nanosized PS latexes in the range of 1.0-3.0 pm were prepared [61] by dispersion polymerization of styrene in isopropanol water media using poly(acrylic acid) (PAA) as a steric stabilizer and 2,2-azobis isobutyronitrile (AIBN) as initiator. Styrene/acrylate monomers, acrylic acid, 2-hydroxy-ethyl methacrylate (HEMA), and dimethylaminoethyl methacrylate were copolymerized onto one of the previously synthesized latex particles to obtain the different surface functionalities. 

In the case of miniemidsion polymerization, aqueous droplets are generated by sonication of the two-phase mixture and become stabilized in organic solvent by oil-soluble surfactants. The kinetically stable emulsion is formed usually at surfaaant concentration below or near its CMC. The inverse miniemulsion approach has been successfully used for the preparation of hoUow PNIPAM miaosphaes or PNIPAM miaogels functionalized by AAc. The synthesis of miaogels based on AAc, AAm, and hydroxy ethyl methacrylate (HEMA) was reported. The size of the miaogels prepared in invase miniemulsion systems typically varies between 150 and 300 nm. 

Sanders and Domb (1990) described reservoir devices using hydrogel membranes to control the release of polypeptides and various growth hormones. The hydrogels used as the rate-limiting membrane barriers for the release of drug were copolymers of hydroxy ethyl methacrylate (HEMA),... 

Multifunctional initiators, produced by dendrimer techniques, have been used to synthesize dendrimer-like star-block copolymers by ATRP method (Hedrick et al., 1998). Starting from a hexafunctional initiator, e-caprolactone was polymerized and each hydroxyl group was then chemically transformed into two 2-bromo-isobutyrate moieties, which were used to initiate the ATRP of either MMA or a mixture of MMA and hydroxy ethyl methacrylate (HEMA) to produce, in the latter case, dendrimer-hke star-block copolymer composed of a poly(e-caprolactone) core... 

Typically, an automotive quality acrylic will be formulated with a mixture of monomers selected fixim styrene (S), methyl methacrylate (MMA), butyl methacrylate (BMA) and butyl acrylate (BA). The hydroxy functionality is introduced via a monomer such as hydroxy ethyl acrylate (HEA) or hydroxy ethyl methacrylate (HEMA) to give hydroxyl values of between 50 and 120 mgKOH/g of solid resin. In addition, a small quantity... 

Figure 3. Effect of polymer concentration on the viscosity changes on reaction between styrene-hydroxy ethyl methacrylate copolymer (2.2 mole % HEMA) and hexamethylene diisocyanate in toluene at 80° C. [2VCO]0 [OH 0 = 1. Polymer concentrations 0.047% (gram/dl.) (%), 0.134% (gram/dl.)...

As for polymer materials used for encapsulation of some low molecular weight drugs, such as cytostatics, antibiotics, etc., which are more stable compared with animal cells or biopolymers (DNA, proteins, peptides, etc.), the list of polymer materials used for their encapsulation is more extended. It includes a series of synthetic polymers as well as their copolymers with namral polymers. We could mention polyacrylates, for example, polyaUcylcyanoacrylates [11], polyester-poly(ethylene glycol) [12], poly(epsilon-caprolactone) [13], polyethylenimine-dextran sulfate [14], dextran-HEMA (hydroxy-ethyl-methacrylate) [15]. 

The acrylic monomers preferred in the preparation of UV curable inks and coatings or in the photoprepolymer printing plate procedure are 2-hydroxyethyl acrylate (2-HEA), 2-hydroxypropyl acrylate (2-HPA), 2-hydroxypropyl methacrylate (2-HPMA), 2-hydroxy-ethyl methacrylate (2-HEMA) and 2-ethylhexyl acrylate (2-EHA). Also, 2-HPMA is used in light-sensitive compositions for fissure sealant adhesives or bonding preparations in dentistry and in Napp printing plates. Various mono(meth)acrylates can be used in water-based acrylic latex paints. Plastics dispersions of acrylic polymers are used as binders or thickeners in paints as well as in cosmetic creams. The monomer content is usually less than 0.3% (Bjorkner 1995). 

PP ABS PP-g-HEMA PP grafted with 2-hydroxy ethyl methacrylate improved dispersion and mechanical properties of ABS/PP blends 62... 

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