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In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (−OH). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, three and four hydroxyl groups are diols, [1] triols, [2] and tetrols, [3] [4] respectively.
The generalised chemical structure of polyisocyanurate showing the isocyanurate group. The polyols are abbreviated as R-groups.. Polyisocyanurate (/ ˌ p ɒ l ɪ ˌ aɪ s oʊ s aɪ ˈ æ nj ʊər eɪ t /), also referred to as PIR, polyol, or ISO, is a thermoset plastic [1] typically produced as a foam and used as rigid thermal insulation.
n.o.s. = not otherwise specified meaning a collective entry to which substances, mixtures, solutions or articles may be assigned if a) they are not mentioned by name in 3.2 Dangerous Goods List AND b) they exhibit chemical, physical and/or dangerous properties corresponding to the Class, classification code, packing group and the name and description of the n.o.s. entry [2]
Its major application is its use for the production of polyether polyols for use in making polyurethane plastics. It is a chiral epoxide , although it is commonly used as a racemic mixture . This compound is sometimes called 1,2-propylene oxide to distinguish it from its isomer 1,3-propylene oxide, better known as oxetane .
Liquid resin blends and isocyanates may contain hazardous or regulated components. Isocyanates are known skin and respiratory sensitizers. Isocyanates are known skin and respiratory sensitizers. Additionally, amines, glycols, and phosphate present in spray polyurethane foams present risks.
Relevant to resins, pentaerythritol is a precursor to other polyol, such as dipentaerythritol: [8] 2 C(CH 2 OH) 4 → O[CH 2 C(CH 2 OH) 3] 2 + H 2 O. Esters of pentaerythitol are biodegradable, [9] [10] and they are used as transformer oils. [11] Due to a very high flash point they also find some use in lubricating gas turbines. [12]
Hazard statements form part of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). They are intended to form a set of standardized phrases about the hazards of chemical substances and mixtures that can be translated into different languages.
Therefore, many poly-alpha-olefins do not crystallize or solidify easily and are able to remain oily, viscous liquids even at lower temperatures. [10] Low molecular weight poly- alpha -olefins are useful as synthetic lubricants such as synthetic motor oils for vehicles and can be used over a wide temperature range.