Propylene glycol chemical structure

Hydroxy-terminated polyester (HTPS) is made from diethylene glycol and adipic acid, and hydroxy-terminated polyether (HTPE) is made from propylene glycol. Hydroxy-terminated polyacetylene (HTPA) is synthesized from butynediol and paraformaldehyde and is characterized by acetylenic triple bonds. The terminal OH groups of these polymers are cured with isophorone diisocyanate. Table 4.3 shows the chemical properties of typical polymers and prepolymers used in composite propellants and explosives.E4 All of these polymers are inert, but, with the exception of HTPB, contain relatively high oxygen contents in their molecular structures. 

Homopolymers of PO and other epoxides are named a number of ways after the monomer, eg, poly(propylene oxide) (PPO) or polymethyloxirane from a structural point of view, polyoxypropylene or poly(propylene glycol) or from the Chemical Abstracts (CA) name, poly[oxy(methyl-l,2-ethanediyl)], CC-hydro- CO-hydroxy-. Common names are used extensively in the literature and in this article. 

Emulsifiers. The chemical structures of emulsifiers, or surfactants, enable these materials to reduce the surface tension at the interface of two immiscible surfaces, thus allowing the surfaces to mix and form an emulsion. An emulsifier consists of a polar group, which is attracted to aqueous substances, and a hydrocarbon chain, which is attracted to lipids. Emulsifiers include mono- and diglycerides, lecithin, propylene glycol esters, luctylated esters, sorbttan and sorbitol esters, polysorbate.x, and sucrose esters. 

Scheme 4.1 Chemical structures of the principal membrane, a poly(ethylene glycol)diacrylate (PEGda). b poly(ethylene oxide) (PEO). c poly(propylene glycol)diacrylate (PPGda). d 2-aminoethylmethacrylate (AEMA) hydrochloride, e poly(ethylene glycol)urethane dimethacrylate (PEGudm) [53]...

Scheme 5 Chemical structures of poly(y-benzyl-L-glutamate)-b-poly(propylene glycol)-b-poly(y-benzyl-L-glutamate) (PBLG-PPG-PBLG) and poly(y-methyl-L-glutamate)-b-polytetrahydrofuran-b-poly(y-methyl-L-glutamate) (PMLG-PTHF-PMLG)...

Polyols used for this purpose include trimethylol propane and propylene glycol. Systems containing urethane-acrylate oligomers bearing doubly-functionalized isocyanate groups are commercially available [24]. The chemical structure... 

InP(lll) substrates by anodic, chemical, and thermal oxidation was studied [55]. The anodization was carried out in an aqueous solution of ammonium citrate and propylene glycol at an applied potential of 120 V. Concentrated nitric acid was used for the chemical oxidation at 80°C for 15 min, and the thermal oxidation occurred in a flow of wet oxygen, Tq = 450°C, ThjO = 95°C. The oxide thickness was 80-150 nm. The effect of a thermally deposited metallic coating (Au or Al, d = 0.2-0.3 xm) on the oxide chemical composition was studied by IRRAS. Conditions of optimum and degraded electrophysical characteristics of the MOS structures were achieved by annealing at 300 and 530°C, respectively, for 1 h in a mixture of N2 and O2. 

Polyesters are macromolecules made by reacting a diacid or dianhydride with a dihydroxy compound (diols). To make unsaturated polyesters, maleic anhydride or fumeric acid is used in addition to a saturated acid, which provides unsaturation in the structure. The most commonly used anhydrides are maleic anhydride (unsaturated) and phthalic anhydride (saturated). The commonest diols are ethylene glycol or propylene glycol. Use of an unsaturated anhydride is very critical to provide unsaturation in the structure, which is utilised to cure the resin by free-radical polymerisation. The chemical reaction for the synthesis of UPE is shown in Figure 2.13. 

---