Polypropylene glycol explained

Polypropylene glycol or polypropylene oxide is the polymer (or macromolecule) of propylene glycol.[1] Chemically it is a polyether, and, more generally speaking, it's a polyalkylene glycol (PAG) H S Code 3907.2000. The term polypropylene glycol or PPG is reserved for polymer of low- to medium-range molar mass when the nature of the end-group, which is usually a hydroxyl group, still matters. The term "oxide" is used for high-molar-mass polymer when end-groups no longer affect polymer properties. Between 60 and 70% of propylene oxide is converted to polyether polyols by the process called alkoxylation.

Polymerization

Polypropylene glycol is produced by ring-opening polymerization of propylene oxide. The initiator is an alcohol and the catalyst a base, usually potassium hydroxide. When the initiator is ethylene glycol or water the polymer is linear. With a multifunctional initiator like glycerine, pentaerythritol or sorbitol the polymer branches out.

Conventional polymerization of propylene oxide results in an atactic polymer. The isotactic polymer can be produced from optically active propylene oxide, but at a high cost. A salen cobalt catalyst was reported in 2005 to provide isotactic polymerization of the prochiral propylene oxide[2]

Properties

PPG has many properties in common with polyethylene glycol. The polymer is a liquid at room temperature. Solubility in water decreases rapidly with increasing molar mass. Secondary hydroxyl groups in PPG are less reactive than primary hydroxyl groups in polyethylene glycol. PPG is less toxic than PEG, so biotechnologicals are now mainly produced with PPG.[3] [4] [5]

Uses

PPG is used in many polyurethane formulations.[6] [7] Synthesis of waterborne polymers has been a feature with this substance.[8] As the basic building block is propylene oxide, there are 3 carbons per oxygen on the backbone. This confers some degree of water miscibility though not as good as ethylene oxide based molecules.[9] It is used to synthesize the epoxy reactive diluent and flexibilizer, Poly(propylene glycol) diglycidyl ether.[10] [11] Another use of PPG is as a surfactant, wetting agent and dispersant in leather finishing.[12] PPG is also employed as a reference and calibrant in mass spectrometry and HPLC.[13] [14] PPG and derivatives may be used as defoamers in drilling and other applications.[15] [16] It is also used as a primary ingredient in the making of paintballs.[17] It has been evaluated as a corrosion inhibitor.[18]

External websites

Notes and References

  1. Web site: PubChem . 2-(2-Hydroxypropoxy)propan-1-ol . 2022-11-14 . U.S. National Library of Medicine . en.
  2. Peretti KL, Ajiro H, Cohen CT, Lobkovsky EB, Coates GW . A highly active, isospecific cobalt catalyst for propylene oxide polymerization . Journal of the American Chemical Society . 127 . 33 . 11566–7 . August 2005 . 16104709 . 10.1021/ja053451y .
  3. Thurman EM, Ferrer I, Rosenblum J, Linden K, Ryan JN . Identification of polypropylene glycols and polyethylene glycol carboxylates in flowback and produced water from hydraulic fracturing . Journal of Hazardous Materials . 323 . Pt A . 11–17 . February 2017 . 26947804 . 10.1016/j.jhazmat.2016.02.041 . Special Issue on Emerging Contaminants in engineered and natural environment . free .
  4. Wang R, Hughes T, Beck S, Vakil S, Li S, Pantano P, Draper RK . Generation of toxic degradation products by sonication of Pluronic® dispersants: implications for nanotoxicity testing . Nanotoxicology . 7 . 7 . 1272–1281 . November 2013 . 23030523 . 3657567 . 10.3109/17435390.2012.736547 .
  5. Thangavelu SA, Mukherjee M, Layana K, Kumar CD, Sulthana YR, Kumar RR, Ananthan A, Muthulakshmi V, Mandal AB . 6 . 2020-06-15 . Biodegradable polyurethanes foam and foam fullerenes nanocomposite strips by one-shot moulding: Physicochemical and mechanical properties . Materials Science in Semiconductor Processing . en . 112 . 105018 . 10.1016/j.mssp.2020.105018 . 213206957 . 1369-8001.
  6. Chattopadhyay DK, Raju NP, Vairamani M, Raju KV . 2008-04-01 . Structural investigations of polypropylene glycol (PPG) and isophorone diisocyanate (IPDI) based polyurethane prepolymer by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-mass spectrometry . Progress in Organic Coatings . en . 62 . 2 . 117–122 . 10.1016/j.porgcoat.2007.09.021 . 0300-9440.
  7. Xu Z, Cui Y, Li T, Dang H, Li J, Cheng F . July 2020 . Enhanced Mechanical and Shape Memory Properties of Poly(propylene glycol)‐Based Star‐Shaped Polyurethane . Macromolecular Chemistry and Physics . en . 221 . 13 . 2000082 . 10.1002/macp.202000082 . 225563251 . 1022-1352.
  8. Kim KJ, Hu R, Grove JL . Arkema Inc . US . Water soluble polymers and polymer adducts along with aqueous solutions thereof Patent . 10920011 . 16 February 2021 .
  9. Howarth GA . Synthesis of a legislation compliant corrosion protection coating system based on urethane, oxazolidine and waterborne epoxy technology . 36-28, 52-60 . Master of Science . April 1997 . Imperial College . London .
  10. Crivello JV . 2006 . Design and synthesis of multifunctional glycidyl ethers that undergo frontal polymerization . Journal of Polymer Science Part A: Polymer Chemistry . 44 . 21 . 6435–6448 . 10.1002/pola.21761 . 2006JPoSA..44.6435C . 0887-624X.
  11. US. 1992-11-10. Ciba-Geigy Corp.. 5162547. Process for the preparation of glycidyl ethers.
  12. Zgoła-Grześkowiak A, Grześkowiak T, Zembrzuska J, Łukaszewski Z . Comparison of biodegradation of poly(ethylene glycol)s and poly(propylene glycol)s . Chemosphere . 64 . 5 . 803–809 . July 2006 . 16343594 . 10.1016/j.chemosphere.2005.10.056 . 2006Chmsp..64..803Z .
  13. Rychłowska J, Zgoła A, Grześkowiak T, Lukaszewski Z . Isolation of poly(propylene glycol)s from water for quantitative analysis by reversed-phase liquid chromatography . Journal of Chromatography A . 1021 . 1–2 . 11–17 . December 2003 . 14735971 . 10.1016/j.chroma.2003.09.003 .
  14. Castillo M, Ventura F, Barceló D . 1999-04-01 . Sequential solid phase extraction protocol followed by liquid chromatography–atmospheric pressure chemical ionization–mass spectrometry for the trace determination of non ionic polyethoxylated surfactants in tannery wastewaters . Waste Management . en . 19 . 2 . 101–110 . 10.1016/S0956-053X(99)00004-5 . 0956-053X.
  15. Tan SN, Pugh RJ, Fornasiero D, Sedev R, Ralston J . February 2005 . Foaming of polypropylene glycols and glycol/MIBC mixtures ] . Minerals Engineering . Reagents '04 . en . 18 . 2 . 179–188 . 10.1016/j.mineng.2004.08.017 . 0892-6875.
  16. Book: Bava L, Mahmoudkhani A, Wilson R, Levy L . 2013-03-23 . New Generation of Green Defoamers for Challenging Drilling and Cementing Applications . New Generation of "Green" Defoamers for Challenging Drilling and Cementing Applications . https://onepetro.org/SPEOKOG/proceedings/13POS/All-13POS/SPE-164504-MS/177686 . en . OnePetro . 10.2118/164504-MS.
  17. Dhiman M, Singh K, Gupta DP, Singh DP, Upmanyu A . 2020-05-04 . Study of excess acoustical and thermo-dynamical parameters of binary solutions of polypropylene glycol-400 and n-alkanols at 303 K . AIP Conference Proceedings . 2220 . 1 . 080001 . 10.1063/5.0001107 . 218923617 . 0094-243X.
  18. Solomon MM, Umoren SA, Israel AU, Etim IG . January 2016 . Synergistic inhibition of aluminium corrosion in H2SO4 solution by polypropylene glycol in the presence of iodide ions . Pigment & Resin Technology . 45 . 4 . 280–293 . 10.1108/PRT-01-2015-0010 . 0369-9420.

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