Prepolymer Explained

In polymer chemistry, the term prepolymer or pre-polymer, refers to a monomer or system of monomers that have been reacted to an intermediate-molecular mass state. This material is capable of further polymerization by reactive groups to a fully cured, high-molecular-mass state. As such, mixtures of reactive polymers with un-reacted monomers may also be referred to as pre-polymers. The term "pre-polymer" and "polymer precursor" may be interchanged.[1]

Polyurethane and polyurea prepolymers

In polyurethane chemistry, prepolymers and oligomers are frequently produced and then further formulated into CASE applications - Coatings, Adhesives, Sealants, and Elastomers. An isocyanate (usually a diisocyanate) is reacted with a polyol. All types of polyol may in theory be used to produce polyurethane prepolymers.[2] [3] [4] [5] [6] These then find use in CASE applications. When polyurethane dispersions are synthesized, a prepolymer is first produced usually modified with DMPA. In polyurea prepolymer production, instead of a polyol a polyamine is used.[7]

Lactic acid as a polymer precursor

See main article: Polylactic acid.

Two molecules of lactic acid can be dehydrated to the cyclic molecule lactide, a lactone. A variety of catalysts can polymerise lactide to either heterotactic or syndiotactic polylactide, which as biodegradable polyesters with valuable (inter alia) medical properties are currently attracting much attention.[8]

Nowadays, lactic acid is used as a monomer for producing polylactic acid (PLA) which later has application as biodegradable plastic.[9] This kind of plastic is a good option for substituting conventional plastic produced from petrochemicals because of low emission of carbon dioxide. The commonly used process in producing lactic acid is via fermentation; to obtain the polylactic acid, the polymerization process follows.

See also

Notes and References

  1. Web site: Prepolymer - an overview ScienceDirect Topics . sciencedirect.com . 2022-02-13.
  2. Howarth G.A "Synthesis of a legislation compliant corrosion protection coating system based on urethane, oxazolidine and waterborne epoxy technology" page 40 Master of Science Thesis April 1997 Imperial College London
  3. Harani . H. . Fellahi . S. . Bakar . M. . 1998 . Toughening of epoxy resin using synthesized polyurethane prepolymer based on hydroxyl-terminated polyesters . Journal of Applied Polymer Science . en . 70 . 13 . 2603–2618 . 10.1002/(SICI)1097-4628(19981226)70:13<2603::AID-APP6>3.0.CO;2-4 . 1097-4628. free .
  4. Shi . Minxian . Zheng . Juanli . Huang . Zhixiong . Qin . Yan . 2011-03-01 . Synthesis of Polyurethane Prepolymers and Damping Property of Polyurethane/Epoxy Composites . Advanced Science Letters . 4 . 3 . 740–744 . 10.1166/asl.2011.1597.
  5. Pokharel . Pashupati . Lee . Dai Soo . 2014-10-01 . High performance polyurethane nanocomposite films prepared from a masterbatch of graphene oxide in polyether polyol . Chemical Engineering Journal . en . 253 . 356–365 . 10.1016/j.cej.2014.05.046 . 2014ChEnJ.253..356P . 1385-8947.
  6. Wang . Lei . Shen . Yiding . Lai . Xiaojuan . Li . Zhongjin . Liu . Min . 2011-05-01 . Synthesis and properties of crosslinked waterborne polyurethane . Journal of Polymer Research . en . 18 . 3 . 469–476 . 10.1007/s10965-010-9438-9 . 56442579 . 1572-8935 .
  7. Howarth . GA . 2003-06-01 . Polyurethanes, polyurethane dispersions and polyureas: Past, present and future . Surface Coatings International Part B: Coatings Transactions . en . 86 . 2 . 111–118 . 10.1007/BF02699621 . 93574741 . 1476-4865.
  8. Vacaras . Sergiu . Baciut . Mihaela . Lucaciu . Ondine . Dinu . Cristian . Baciut . Grigore . Crisan . Liana . Hedesiu . Mihaela . Crisan . Bogdan . Onisor . Florin . Armencea . Gabriel . Mitre . Ileana . November 2019 . Understanding the basis of medical use of poly-lactide-based resorbable polymers and composites - a review of the clinical and metabolic impact . Drug Metabolism Reviews . 51 . 4 . 570–588 . 10.1080/03602532.2019.1642911 . 2019-07-24 . 1097-9883 . 31296117. 195893132 .
  9. DeStefano . Vincent . Khan . Salaar . Tabada . Alonzo . 2020-01-01 . Applications of PLA in modern medicine . Engineered Regeneration . en . 1 . 76–87 . 10.1016/j.engreg.2020.08.002 . 2666-1381. free . 38620328 . 7474829 .

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