Cardanol polymerization

A new crosslinkable polymer was synthesized by the SBP-catalyzed polymerization of cardanol. When HRP was used as catalyst for the cardanol polymerization, the reaction took place in the presence of a redox mediator (phe-nothiazine derivative) to give the polymer. Fe-salen efficiently catalyzed the polymerization of cardanol in organic solvents (Scheme 29). " The polymerization proceeded in 1,4-dioxane to give the soluble polymer with molecular weight of several thousands in good yields. The curing of the polymer took place in the presence of cobalt naphthenate catalyst at room temperature or thermal treatment (150°C for 30 min) to form yellowish transparent films ( artificial urushi ... 

A new crosslinkable polymer was synthesized by the SBP-catalyzed polymerization of cardanol [103]. When HRP was used as catalyst for cardanol polymerization, the reaction took place in the presence of a redox mediator (phenothiazine derivative) to give the polymer [104]. 

Synthetic resins, such as phenoHc and cresyUc resins (see Phenolic resins), are the most commonly used friction material binders, and are usually modified with drying oils, elastomer, cardanol [37330-39-5] an epoxy, phosphoms- or boron-based compounds, or even combinations of two. They ate prepared by the addition of the appropriate phenol and formaldehyde [50-00-0] in the presence of an acidic or basic catalyst. Polymerization takes place at elevated temperatures. Other resin systems are based on elastomers (see Elastomers, synthetic), drying oils, or combinations of the above or other polymers. 

The oligomerization of cardanol with boron trifluoride etharate as the initiator was studied in detail by Antony et al. [171]. The reaction conditions were optimized by using gel permeation chromatography as 140°C with an initiator concentration of 1%. GPC data indicate conversion of all monoene, diene, and triene components into polymer except the saturated component, indicating participation of all the unsaturated components in polymerization. It is possible that the initiation of po-... 

The cationic polymerization of cardanol under acidic conditions has been referred to earlier [170,171], NMR studies [16] indicated a carbonium ion initiated mechanism for oligomerization. PCP was found to be highly reactive with aldehydes, amines, and isocyates. Highly insoluble and infusible thermoset products could be obtained. Hexamine-cured PCP showed much superior thermal stability (Fig. 12) at temperatures above 500°C to that of the unmodified cardanol-formaldehyde resins. However, it was definitely inferior to phenolic resins at all temperatures. The difference in thermal stability between phenolic and PCP resins could be understood from the presence of the libile hydrocarbon segment in PCP. 

John, G. and Pillai, C.K.S. (1992) Self-crosslinkable monomer from cardanol crosslinked beads of poly(cardanyl acrylate) by suspension polymerization. Makromolekulare Chemie Rapid Communications, 13, 255—259. 

Kim YH, Suk An E, Keun Song B et al (2003) Polymerization of cardanol using soybean peroxidase and its potential application as anti-biofilm coating material. Biotechnol Lett 25 1521-1524... 

Kim YH, An ES, Park SY et al (2007) Enzymatic epoxidation and polymerization of cardanol obtained from a renewable resource and curing of epoxide-containing polycardanol. J Mol Catal B Enzym 45 39-44... 

Cardanol, the main component obtained by thermal treatment of cashew nut shell liquid (CNSL), is a phenol derivative having the meta substituent of a C15 unsaturated hydrocarbon chain with one to three double bonds as the major component. The SBP-catalyzed polymerization of cardanol in aqueous acetone produced the oily soluble polymer with Mn of several thousands.38 The carbon—carbon unsaturated group in the side chain of cardanol did not change during the polymerization. The curing by... 

Model complexes of peroxidase were used as catalysts for the oxidative polymerization of phenols. Hematin, a hydroxyferriprotoporphyrin, catalyzed the polymerization of />ethylphenol in an aqueous DMF.63 Iron—A/,A/ -ethylenebis(salicylideneamine) (Fe—salen) showed high catalytic activity for oxidative polymerization of various phenols.64 The first synthesis of crystalline fluorinated PPO was achieved by the Fe—salen-catalyzed polymerization of 2,6-difluorophenol. Cardanol was polymerized by Fe— salen to give a cross-linkable polyphenol in high yields. 

Many efforts have been made to base polymers on furfural made from pentoses.159 The polymers may be useful, but tend to have lower thermal stability than the usual synthetic polymers. Polyesters based on furfural were mentioned earlier. The acid-catalyzed polymerization of furfuryl alcohol is used in foundry cores.160 Furfural has been condensed with cardanol (m-pentadecadienylphenol) from cashew nut shell oil in the presence of other phenols to produce polymeric resins.161 Cardanol and hydrogenated cardanol have been polymerized with horseradish peroxidase to soluble polymers in up to 85% yield.162 Plasticizers that are effective in polyvinyl chloride, such as (12.31), have been made from furfural.163... 

The properties of phenolic lipids have tended to be dominated by technological aspects and it is only comparatively recently that potential biological usefulness has come to the fore. For example, products derived from the Anacardiacae occidentale, notably cardanol obtained by semisynthesis through thermal decarboxylation were all directed to polymeric and technical applications and the vast industrial literature [246] contains only two references to insecticidal uses of chlorinated cardanol [247]. 

Selective reaction of cardol in preference to cardanol under Mannich reaction conditions with diethylenetriamine (or 4-aminobutane) and aqueous formaldehyde in methanolic solution resulted in the separation, as a lower layer, of the cardol in the form of a low polymeric Mannich base. Recovery of cardanol from the upper layer and high vacuum distillation afforded pure material containing only traces of 2-methylcardol (ref. 189). Thus technical CNSL (1 mole average mol. wt. 303g) with 40% aqueous formaldehyde (1.2 mole CHjO) and diethylenetriamine (0.125 mole) in methanol (1250ml) afforded after 30mins a dark methanol-insoluble lower... 

With the aid of gradient elution, a reversed phase partition method and an internal standard, considerable progress has been made in the quantitative determination of each constituent of the main component phenols present in technical CNSL and in natural cashew-nut shell liquid provided that relative molar response (RMR) factors are used. A typical quantitative HPLC analysis of the technical material indicated cardanol (67.8%), cardol (18.2%), 2-methylcardol (3.3%), minor constituents (3.3%) and polymeric material (7.4%). 

C atalytic site of peroxidase is a heme, which is rapidly oxidized in its free form to hematin. p-Ethylphenol was polymerized using hematin as catalyst in an aqueous DMF (325). Iron-)VA -ethylenebis(salicyhdeneamine) (Fe-salen) also can be regarded as model complex of peroxidase. Fe-salen catalyzed an oxidative polymerization of various phenols such as 2,6-dimethylphenol, bisphenol A, cardanol, and urushiol analogues (251,293,326-329). The polymerization of 2,6-difluorophenol by Fe-salen produced a crystalline fluorinated PPO derivative (330). 

A new way to realize polymers from m-substituted phenols having a bulky substituent via HRP catalysis is polymerization in the presence of a redox mediator [146]. Cardanol is a phenol derivative from a renewable resource, which has a very bulky substituent in the meta position a C15 imsaturated hydrocarbon chain with one to three double bonds. Thus, cardanol was polymerized by SBP, while HRP did not initiate this polymerization [147]. However, the HRP-catalyzed polymerization took place in the presence of N-ethyl phenothiazine and phenothiazine-lO-propionic acid. The structure and properties of the resulting polymers have been reported to be siniilar to those made by SBP catalysis. Thus, the two presented phenothiazine derivatives most likely act as a mediator for electron transfer between HRP and cardanol, as demonstrated in Fig. 7 [146]. 

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... 

Scheme 25 Polymerization of cardanol using Fe(II)-salen catalyst...

The urushi lacquer has been used for more than 5000 years in China " and it is known as a highly durable material. Polymerization of urushiol, the major component of the lacquer, involves laccase-catalyzed dimerization and aerobic oxidative polymerization, " and the drying process takes a very long time. Several studies on shortening of this time have been carried out UV curing " " and hybridizing with other reactive polymers or monomers. " " Cardanol has a similar structure to urushiol, and the enzymatic oxidative polymerization of cardanol were reported by three research groups. " The development of the polymerization process leads to artificial urushi . 

Figure 15. Schematic Representation of Oxidative Polymerization of Cardanol by Using Fe-salen as Catalyst. [272]...

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