Resins production from renewable resources

A rather impressive Hst of materials and products are made from renewable resources. For example, per capita consumption of wood is twice that of all metals combined. The ceUulosic fibers, rayon and cellulose acetate, are among the oldest and stiU relatively popular textile fibers and plastics. Soy and other oilseeds, including the cereals, are refined into important commodities such as starch, protein, oil, and their derivatives. The naval stores, turpentine, pine oil, and resin, are stiU important although their sources are changing from the traditional gum and pine stumps to tall oil recovered from pulping. 

The research emphasized by industry falls roughly into four categories. First, the recovery or production of today s synthetic resin raw materials directly from renewable resources or as byproducts in waste streams from industries that utilize renewable resources themselves, such as pulp and paper. Examples would be ... 

A wood-based composite can be defined as a composite material mainly composed of wood elements. These wood elements are usually bonded together by a thermosetting adhesive (wood truss products could also be regarded as wood-based composites, but connected by metal connectors). The commonly used adhesives include urea-based adhesive (such as urea formaldehyde resin), phenolic-based adhesive (including phenol resorcinol adhesives), isocyanate-based adhesive, and adhesives from renewable resources (like soybean, lignin etc). The wood elements in wood composites can be in many different forms such as ... 

The beginning of the twentieth century witnessed the birth of a novel class of materials, the synthetic polymers based on monomers derived from fossil resources, but the progress associated with them was relatively slow up to the Second World War and did not affect substantially the production and scope of the naturally based counterparts. Some hybrid materials, arising from the copolymerization between both types of monomers were also developed at this stage as in the case of the first alkyd resins. Interestingly, both monomers used in the first process to synthesize nylon in the late 1930s were prepared from furfural, an industrial commodity obtained from renewable resources, in a joint venture between Quaker Oats and DuPont. 

Due to the rapidly increased production cost of fossil (petroleum)-based chemicals, fermentatively produced fumaric acid from renewable resources could replace current petrochemically based maleic acid as unsaturated dibasic acid mainly in the polyester resin industry but also in medicine and food industries in the nearby future. However, this can be achieved only if the bio-based production process for fumaric acid would be economically competitive with the current fossil-based process. This change requires the improvement of the large, past-operating fermentation processes for acid production in many aspects, such as production of free acid at a low pH, product yield and productivity, cheap and renewable raw material, and problems related to cell morphology and mass transfer. 

Another compound which has been found to somewhat imitate the active site of peroxidases is the commercially available Fe(II)-salen catalyst. This catalyst was used successfully to produce phenol polymers, which could be of interest for industrial production [153,154]. For example, cardanol can be polymerized by the Fe(II)-salen catalyst [155]. Due to the unsaturated bonds in the side chain of the cardanol components, the resulting polymers could be thermally cured, or cured by use of cobalt naphthenate to give brilliant films with a high-gloss surface. This reaction proves that reactive prepolymers can be synthesized from renewable resources (cardanol is the main component obtained by thermal treatment of cashew nutshell liquid). This process could be a true alternative to conventional phenol-formaldehyde resins (Scheme 25) [ 155]. Other non-heme iron complexes have been foimd to... 

The promise of large-scale low-cost fermentations from renewable resources, especially corn, has spurred interest in the United States to develop chemical production for large-volume chemicals using bio-based processes. Succinic acid can be converted by hydrogenation to 1,4-butanediol, which has a world market in excess of 500,000 metric tons. Butanediol is used to produce polybutylene terephthalate (PBT) resins that have desirable mechanical and thermal properties and are a high-performance version of polyethylene terephthalate resins (PET). Also, 1,4-butanediol is a precursor of tetrahydrofuran, which can be polymerized to polytetrahydrofuran (PTHF). Gamma butyrolactone (GBL) can also be derived from 1,4-butanediol, and much of GBL is used to manufacture the solvent N-methyl-2-pyrrolidone (Szmant 1989). 

Lactic acid can be produced from a petrochemical route or from fermentation (6,7). The petrochemical route can only produce racemic mixtures of lactic acid, whereas fermentation canproduce optically pure isomer. D(-)-Lactic acid is toxic and must be limited in animal feeds (8), and an optically pure lactic acid is required to produce a specific PLA (9). In addition, fermentation utilizes renewable resources thatmake fermentationmore attractive than the petrochemical route. Extractive fermentation, which couples fermentation with on-line product removal, can eliminate end product inhibition and increase product yield, final product concentration, and reactor productivity. A number of extractive fermentation methods have been reported in the literature, including solvent extraction (10-12), precipitation (13), electrodialysis (14,15), adsorptionby ion-exchange resin (16-18), and an aqueous two-phase system (19-20). 

If this method proves to be commercially feasible, a renewable and abundant waste product of forest products manufacture could replace expensive petrochemicals. Additionally, use of an inexpensive waste product from processing of forest products could materially reduce adhesive costs and expand opportunities for manufacture of structural materials from low-quality wood. This benefit is particularly important since the difficulty in producing large, strong, structural members from timber resources of declining quality is growing exponentially with time. The cost-benefit ratios of replacing PRF resins with extracts from conifer barks are, therefore, quite favorable in a honeymoon system. 

Since the oil shortages of the 1970s, there has been a sustained search for materials to replace the petroleum-based resins used as durable adhesives for exterior wood products. Such alternatives are considered important, because supplies of petrochemicals for use in the wood industry could again become undependable. Ideally, the source of material for an adhesive would be readily available, possibly from materials already found near or used by wood processing plants, for example, agricultural or wood-based renewable resources. The purpose of this investigation was to explore the use of carbohydrates as constituents in water-resistant adhesives. 

Other collaborations like this one have produced a Dow product called Wood-stalk, a formaldehyde-free polyurethane resin particleboard from a harvested wheat straw fiber, a renewable resource. Dow acknowledges the importance of stakeholder collaboration in their business strategy. Green building practices... 

Which renewable resources can be used industrially From forestry, wood and resins are available from agriculture, oleiferous fruits, sugar beets, sugar cane, corn, and potatoes and from the meat and fish industries, animal waste such as bones. From these primary products the following ingredients - the actual renewable resources - are obtained ... 

Phenol-formaldehyde resins are among the most important polymeric adhesives used in the wood based composite panel manufacturing industries [1]. Phenolic resins are prepared by the reaction of phenol or any substituted phenol with formaldehyde or other aldehydes, in the presence of acidic or basic catalyst. The price of phenol depends on the oil price and is likely to ever increase due to shortage of fossil resources. Hence, several lignin substitute products based on renewable materials derived from annual plants such as flax [2, 3] or kenaf [4], agricultural waste such as sugar cane bagasse [5] and wheat straw [6] or by-products from the... 

Cellulose materials are good candidates to use as fillers in polymers, especially with their recent importance in recycling. There are many different types of materials available, such as wood flour, recycled newspaper, nut shells, and starch. These materials have several advantages, including low cost, low density, low abrasiveness, and they are a renewable resource. However, they do have a number of disadvantages, such as low thermal stability, high moisture absorption, and poor interfacial adhesion. Despite these problems, there are a number of products available in the marketplace. One of the most visible is plastic lumber. Most plastic lumber is made using polyethylene as the base resin and contains up to 50% wood. Much of the time, both resin and wood feedstocks come from recy-... 

Research projects carried out at A F clearly indicate that effective plasticisers for PVC and other resins and binders and additives for alkyd based decorative paints can be based on those raw materials which are the least undisputed from an environmental point of view i.e. renewable resources. These products are not only renewable based but also durable. Provided a positive life cycle analysis, after further R D work plasticisers and high-solid or water borne alkyd paints based on renewables therefore can make an important contribution to a sustainable chemical industry. 

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