Progress in Polymer Science 33 (2008) 1199–1215 Contents lists available at ScienceDirect Progress in Polymer Science journal homepage: www.elsevier.com/locate/ppolysci Condensation polymers from natural oils Vinay Sharma, P.P. Kundu ∗ Department of Chemical Technology, Sant Longowal Institute of Engineering and Technology, Sangrur, Punjab 148106, India article info Article history: Received 23 August 2007 Received in revised form 1 June 2008 Accepted 1 July 2008 Available online 23 August 2008 Keywords: Soybean oil Castor oil Nahar seed oil Polyols Condensation polymers Polyurethanes Polyesters abstract Innovative technologies and competitive industrial products are reducing the dependence on petrochemicals for the production of polymers. Increasing concerns about the deteri- orating environment caused by conventional polymers have directed worldwide research toward renewable resources. Vegetable oils are one of the most readily available alterna- tive renewable resources. The functional groups present in natural oils can be activated for condensation polymerization. Accordingly, various types of useful condensation poly- mers, such as polyurethanes, polyesters and polyethers, are being produced by this route. The incorporation of natural oils into the polymer chain allows tailoring the properties of polyurethane products, for their widespread applications. © 2008 Published by Elsevier Ltd. Contents 1. Introduction ....................................................................................................................... 1199 1.1. Polyols ..................................................................................................................... 1200 1.2. Polyurethanes ............................................................................................................. 1200 2. Polymers based on soybean oil polyols .......................................................................................... 1200 3. Polymers and IPNs based on castor oil polyols ................................................................................... 1205 3.1. Polymers based on castor oil polyols ...................................................................................... 1205 3.2. Interpenetrating and semi-interpenetrating networks based on castor oil .............................................. 1209 4. Polymers based on nahar seed oil polyol ......................................................................................... 1212 5. Other polymers based on oil polyols ............................................................................................. 1213 6. Conclusions ....................................................................................................................... 1214 References ........................................................................................................................ 1214 1. Introduction Since the synthesis of polyurethanes by Bayer in 1937 [1], their utilization has become ubiquitous. These polymers are synthesized by reacting three basic compo- nents: polyisocyanate, polyhydroxyl containing polymer ∗ Corresponding author. E-mail address: ppk23@yahoo.com (P.P. Kundu). (i.e., polyester or polyether polyol) and a chain extender (usually a low molecular weight diol or diamine). Cur- rently, the majority of polyols (polyether and polyester polyols) is derived from petrochemicals, a resource sub- ject to depletion. Hence, bio-based materials are receiving wide attention as the oil crisis and threat of global warming deepen. The synthesis of bio-based materials from natural oils affords an alternative route [2–4] to natural oil-based addition polymers, which we discussed in an earlier review [5]. 0079-6700/$ – see front matter © 2008 Published by Elsevier Ltd. doi:10.1016/j.progpolymsci.2008.07.004