JEC COMPOSITES MAGAZINE - Issue #59 - August/September 2010 - 19

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A full review of bio-based monomers and polymers, including those not mentioned in this article, can be found in the report “The state-of-the-art on bioplastics: products, markets, trends and technologies”. This report discusses questions on related markets, investment plans, trends, expectations, new opportunities, issues and technologies. Copies can be obtained through the website http://www.lifetecvision.com/Shop.aspx?ReportGroup=2501 possibilities of these bio-based polyols are rapidly growing due to improved functionalization technologies. The main fatty acid from castor oil is ricinoleic acid (12-hydroxy-9-cisoctadecenoic acid), with a hydroxyl group on C12 and a C=C double bond in the middle of the chain. Soybean oil has C=C double bonds but no hydroxyl groups. Esters or alcohols can be produced through oxidation of this double bond. These materials clearly have limited hydroxyl functionalities, so chemistry is required to modify them so that a larger portion of these raw materials can be used for the desired polyols. In the meantime, castor oil is reacted with diisocyanates to produce polyurethanes for coating and foam applications, while castor oil derivatives are used to produce PU foam for mattresses. The use of plant-based polyols for PU products attracted considerable market attention and demand in 2004, although early developments date back to the previous century. Several companies were forerunners in using these products for seats, body panels, armrests, etc. In addition to polyurethanes, there is also a high potential for using NOPs in unsaturated polyester resins, alkyds (done for some time now) and thermoplastic elastomers like copolyester elastomers and polyurethane elastomers. Today, NOPs are used in rigid insulating foams for building and appliance insulation with renewable contents up to 70%, thus resulting in rigid PU foams with renewable contents of ≥ 15%. Other polyol-based products with up to 20% renewable content are used in the production of flexible slabstock foam. These are suitable substitutes for the current commercial petroleum-based polyols. Of course, the challenge remains to further increase the renewable feedstock content without losing physical, mechanical and durability properties of the end products. A polyol derived from castor oil by up to 31% was introduced in 2008. It can be used to manufacture slabstock foams for mattress production, which would then contain up to 25% renewable material. While odour, emission and processing problems used to keep NOPs out of flexible slabstock, these deficiencies have now been resolved. This drop-in is claimed to have no effect on processing or foam properties. Another series of products are currently used in flexible polyurethane cushioning for a growing number of applications, including furniture, bedding, automotive and carpeting. The BiOH® polyols are used to replace a growing portion of petrochemical-based polyols in downstream PU products. These products should be further developed to increase the renewable content of the resulting polyurethanes and to make them suitable for other applications (in addition to flexible foam). A distinct multistep process is used to break down and functionalize vegetable oil molecules to make products with high renewable content (10-30%) without the odour often associated with bio-based

polyols in PU foams. This process also makes them suitable for many automotive, furniture & bedding, metal & plastic coatings, carpets, footwear, adhesives and sealants applications. By the end of this decade, we expect to see a significant further increase in the use of bio-polyol in PU foam products.

Renewable monomers
An ever larger number of renewable monomers for thermoplastics and thermosets are being investigated for cost-attractive manufacturing through white biotechnology routes, with several of them on the market already. A distinction can be made between monomers that used to be produced from fossil resources and monomers that are based on renewable resources and bring differentiation options to the polymer industry. There are several examples of bio-based monomers that are relevant for thermosets, but are still produced in small quantities or are in the development stage. Itaconic acid, isosorbide, isoidide, long chain diols, diacids, diamines and 2,5furandicarboxylic acid (FDCA) are examples of renewable monomers that are being developed and investigated for use in thermosets, thermoplastics and composite materials. Recently, isosorbide has been investigated to replace bisphenol-A in polycarbonates (PC) and in epoxy resins. Its cycloaliphatic structure should provide better UV properties and extra rigidity to the polymer chain but the question is: to what extent will this suffice to replace some of the existing resins. Its moisture sensitivity appears to be lower than that of the original PC. A 300 MT/ year demonstration plant is under construction for bio-PC based on isosorbide.

Structure of isosorbide based polycarbonate

No59 August - September 2010 / jec composites magazine

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JEC COMPOSITES MAGAZINE - Issue #59 - August/September 2010

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