Oligocarbonate diols obtained from carbonate „green monomers” as soft segments of polyurethanes
Journal Title: CHEMIK nauka-technika-rynek - Year 2010, Vol 64, Issue 4
Abstract
This paper presents various methods of oligocarbonate diols (OWDs) synthesis based on environmentally friendly materials. Taking into account the price and availability of raw materials, lack of hazardous by-products and the process efficiency, especially attractive methods of oligocarbonate diols obtaining seem to be those in which carbon dioxide and simple esters of carbonic acid such as ethylene carbonate, trimethylene carbonate and dimethyl carbonate are used. We have developed the preparation methods of oligomerols, which do not contain ether units and their macromolecules are exclusively terminated with hydroxyl groups. Depending on the method of synthesis oligocarbonate diols can contain 3 to 13 carbon atoms in the repeating unit and are characterized by molecular weight in the range of 1000-3000. It has been shown that applying the method based on dimethyl carbonate (DMC) when two different diols are used liquid co-oligomers of irregular structure can be obtained. Moreover, applying the polymerization method co oligomers with oligo(dimethylsiloxane) and oligocarbonate blocks can be easily formed when oligo(dimethylsiloxane)diol was used as an initiator for thermal polymerization of trimethylene carbonate. In the paper a new non-isocyanate reaction pathway leading to oligocarbonate diols containing urethane groups was also presented. According to this method the reaction product of alkylene diamine (e.g. hexamethylenediamine) with ethylene carbonate is used as the initiator for polymerization of trimethylene carbonate. The oligocarbonate diols can be used to manufacture biomedical polyurethanes of various purposes. Polyurethanes with oligocarbonate soft segments based on longer diols are particularly attractive as materials for implants due to their resistance to hydrolysis and oxidizing agents. Those based on short diols can be used as biodegradable materials. Polyurethane ilms obtained on the basis of oligocarbonate diols exhibited very good echanical properties: tensile strength, depending on the molecular masses f oligocarbonate diol and its chemical structure, varied from 35 MPa oligo(trimethylene carbonate), Mn = 1500 g/mol) to 50 MPa (oligocarbonate iol based on 1,6-HD/1,4-BD (1/2), Mn = 1400 g/mol), and elongation t a break from 420% (OWD + OSD, Mn = 1720 g/mol) to 750% (oligo(trimethylene carbonate), Mn = 1500 g/mol).
Authors and Affiliations
Karolina Tomczyk, Piotr Pawłowski, Paweł Parzuchowski, Gabriel Rokicki
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