Oil-based polyamides

Vegetable oil-based polyamides are usually prepared either by the crosscondensation polymerisation of diacids with suitable diamines (hexameth-ylene diamine for nylon 6,10 and nylon 6,9), or by the self-condensation polymerisation of amino-acids (o)-aminoundecanoic acid for nylon 11). Cross-condensation is usually a two-step reaction in which the alcoholic salt solution of the reactants is heated under pressure at a high temperature to obtain the desired polyamide. The self-condensation reaction of amino acids is usually carried out in an autoclave. The melted reactant is polymerised under relatively high pressure and temperature. In both the cases the reaction is performed under the blanket of an inert atmosphere. 

What are the different uses of vegetable oil-based polyamides Vegetable oil-modified addition polymers have many potential applications . Explain. 

Thermoplastic polyamides are used in coatings to modify alkyd resins (qv) in thixotropic systems (238) and to plasticize nitroceUulose lacquers (239). DETA-taH oil fatty acid-based polyamides are suggested for use as corrosion inhibitors in alkyd paints (240). Printing inks for fiexo-gravure appHcation on certain paper, film and foil webs rely on EDA- and PDA-based polyamides for their specific performance (241). 

The most important coating appHcation for the nonreactive polyamide resins is in producing thixotropy. Typical coating resins such as alkyds, modified alkyds, natural and synthetic ester oils, varnishes, and natural vegetable oils can be made thixotropic by the addition of dimer acid-based polyamide resins (see Alkyd resins). Specialty high performance coating appHcations often requite the properties imparted by dimer acid components. 

Bio-based and recycled polymers often have short-lifecycles compared to oil-based virgin resins. We studied bio-based (PAX) and recycled (PA6) polyamide (PA) blends [LOU 13]. Scanning electron microscopy (Figure 12.4) shows that the formulations are composed of 75% PA6 and 25% PAX by mass (denoted PA6/PAX (25/75)) and PAX nodules appear in the PA6 matrix. To refine the morphology and improve PA6/PAX interfaces, we conducted reactive compatibilization to couple the... 

Table 11.2 gives a survey about major use areas for adhesives based on renewable sources. The share of renewable raw materials in the sealants market is well below 5%. Numbers in Table 11.2 do not include polyurethanes containing oleochemical-based polyols, vegetable oil-based polyesters and polyamides based on dimer fatty acids in total estimated at 35 mto in 2006, 42 mto in 2010. Projection into 2010 shows that without disruptive innovations the share of natural-based adhesives will further decline to a mere 15% in total. 

Both paints and adhesives are commonly formulated as polymer blends or grafts. In fact, some compositions resemble semi-IPN s or AB crosslinked copolymers (Section 8.7). For example, epoxy adhesive resins are often cured with polyamides (Bikerman, 1968). The product is tougher than materials cured with low-molecular-weight amines, possibly because of a separate amide phase in this AB crosslinked copolymer. A more complex molecular architecture is exhibited by the alkyd resins common in oil-based paints (Martens, 1968, Chapters 3 and 4). The major component is a polyester, which often forms a network structure on drying. The polyester component is reacted with various drying oils, such as linseed oil or tung oil (Martens, 1968, Chapters 3 and 4). These oils form an ester link to the polyester structures and also polymerize through their multiple double bonds. Latex paints always contain thickeners, such as cellulosics, poly(acrylic acid), casein. 

Abstract This chapter describes vegetable oil-based addition polymers and polyamides. It deals with the importance, materials and methods, structure-property relationships and applications of vegetable oil-based addition polymers and polyamides. The chapter also inclndes a short review of such addition polymers and polyamides from various vegetable oils. It is shown that vegetable oils also play a key role in synthesising these industrial polymers. The importance of snch polymers is highlighted, as they can be used in surface coatings and paints and in the antomotive and transport industry. 

Key words vegetable oil-based addition polymers and polyamides, preparation of addition polymers and polyamides, structure-property relationships of addition polymers and polyamides, application of addition polymers and polyamides. 

Polyamides, polyolefins and other vegetable oil-based polymers 209... 

Specialised polymers, which are mainly used in engineering applications in the automobile, aircraft and machinery industries, are known as engineering polymers. In this group, aliphatic polyamides are the most important and most widely used. A large number of aliphatic polyamides are obtained from vegetable oil-based products. Among these nylon 6,10, nylon 11, nylon 6,9 and poly(amido amine) are very important. One of the most important commercially used polymers, nylon 11, is obtained entirely from castor oU, whereas vegetable oil-derived components are only partly used to prepare other polymers. 

The most common application of vegetable oil-modified polyamides is in the surface coatings and paints industry. The dimer acids of tall and soybean oils and amines are used to modify the flow behaviour of paints. This thixotropic flow prevents setting and sagging, enables easy application and improves surface appearance. Vegetable oil-based nylons are used as engineering polymers in the automotive and transport industry for fuel lines. Products are also used for the extruded and moulded components of fuel systems such as filler necks, gas tanks, reservoir modules, filters, fuel rails and vapour recovery systems. Nylon 11 is also used in power coatings to coat metals that must withstand abrasion, impact and corrosion. 

In this approach, AB2 type or other similar monomers such as AB (x = 4, 6, 8, etc.) monomers are polymerised by a polycondensation reaction. Gelation, a general problem in the polymerisation of multifunctional monomers, is avoided by the use of a dilute solution and the slow addition of monomer(s). Vegetable oil-based hyperbranched polyhydrocarbons, polyethers, polyesters, polyamides, and so on may be prepared by this method. 

Triglycerides, Soybean oil. Castor oU, Sunflower oil. Oil-based polymers. Fatty acids, Epoxidized oils. Interpenetrating networks, CrossUnking of oils. Oil-based polyurethanes, OU-hased polyamides. Oil-based polyester-amides. Oil-based alkyd resins. Oil-based polyesters. Oil-based poly(hydroxyalkanoates)... 

There are a number of polymers, notably hydrogenated castor oil and its derivatives, polyamides (Chapter 15) and polyamide-oil or polyamide-alkyd reaction products (Chapter 12), which can be used to impart non-Newtonian viscosity to paints based on non-polar (mainly aliphatic hydrocarbon) solvents. The thickening mechanisms of polymeric additives are not fully established, but the resins have in common the following features borderline solubility in the paints in which they are used and chemical structures involving lengthy soluble non-polar chains (e.g. fatty portions of fatty acids) and polar groups, e.g. -OH, -CONH- and -COOH. 

ADMET has been used to take advantage of several natural polymer feedstocks, mainly plant oils and fatty acids (Figure 13.26) [190]. An initial study optimized the ADMET polymerization of a variety of plant oils, and yields of40—60% were obtained [191]. A set of polyamides were synthesized by ADMET polymerization of monomers ultimately derived from ricinoleic acid, the main fatty acid of castor oil [192]. Similarly, ADMET was utilized to polymerize 1,3-di-lO-undecenoxy-2-propanol, a castor oil-based diene, which was subsequently reacted with... 

Semisynthetic cellulose nitrate and the other cellulosics, polyamides derived from dimer acids, and castor-oil based polyurethanes. 

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