Boron modified phenolics

The development of a solvent reaction between triphenyl borate and paraformaldehyde to produce a boron-modified phenolic resin that flowed at usual processing temperatures has been reported.90... 

Hirohata, T. Misaki, T. Yoshii, M. Bromine, chlorine and boron modified phenolic resins with excellent flame retardance and thermal stability. Zairyo (English translation) 1987, 36 (401), 184-188. 

Abdalla, M.O. Ludwick, A. Mitchell, T. Boron-modified phenolic resins for high performance applications. Polymer 2003, 44 (24), 7353-7359. 

Non-metallic stractures of boron, silicon, phosphorus, and bromine can be bonded to phenolics. In most cases, these resins show an improved thermal stability in comparison to the nonmodified ones [1], Boron modified phenolics are prepared from aryl borates that are synthesized from phenol and boric acid (Scheme 26). The aryl borates react with methanal or 1,3,5-trioxane as shown in Scheme 26 to give boron modified prepolymers [167,168],... 

Crosslinking of boron modified phenolics with 1,3,5,7-tetraazatricyclo-[3.3.3. P jdecane or with epoxides yields thermostable products [169,170], The increased thermal resistance of these materials is attributed to the stractures given in Scheme 27. The boron modified phenolics are applicable as high temperature stable materials in moldings and brake linings. 

Structures in Boron Modified Phenolics that are Sources for Thermal Stability... 

Soirrces for boron modified phenolics are phenol and boric acid. The crosslinked boron modified phenolics possess an increased thermal resistance in comparison to nonmodified products. The boron modified phenolics are applicable as high temperahrre stable materials. 

Commercially available organic bonds include ones based on phenolic and modified phenolic resins, alkyds and polyesters, shellac, polyurethanes, epoxies, and rubbers such as natural, synthetic natural, GRS, Neoprene, and acrylics. Further, polyimide bonds find use in diamond and cubic boron nitride products. 

The controlled thermal decomposition of dry aromatic diazonium fluoborates to yield an aromatic fluoride, boron trifluoride and nitrogen is known as the Schiemann reaction. Most diazonium fluoborates have definite decomposition temperatures and the rates of decomposition, with few exceptions, are easily controlled. Another procedure for preparing the diazonium fluoborate is to diazotise in the presence of the fluoborate ion. Fluoboric acid may be the only acid present, thus acting as acid and source of fluoborate ion. The insoluble fluoborate separates as it is formed side reactions, such as phenol formation and coupling, are held at a minimum temperature control is not usually critical and the temperature may rise to about 20° without ill effect efficient stirring is, however, necessary since a continuously thickening precipitate is formed as the reaction proceeds. The modified procedure is illustrated by the preparation of -fluoroanisole ... 

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. 

To expand the diversity of their libraries Brill et al.16 also modified various heterocycles by alkylation, acylation, or metal-mediated coupling reaction prior to resin capture. A remaining chloro substituent was still available for nucleophilic displacement or a palladium-mediated coupling reaction with anilines, phenols, and boronic acids on solid phase [see Fig. 10 for the preparation of purine derivative (62)]. 

Other materials were also employed to construct electrodes for amperometric detection. For instance, a boron-doped diamond (BOD) electrode was used for amperometric detection of nitroaromatic explosives, organophosphate nerve agents, and phenols. The BOD electrode offers enhanced sensitivity, lower noise, negligible adsorption of organic compounds, and low sensitivity to oxygen [760], In addition, a copper particle-modified carbon composite electrode was used for amperometric detection of glucose in a PDMS chip [761]. 

Although only cardol in CNSL has bifunctionality, attempts have been made to modify cardanol to the same effect. Thus reaction of (15 1)-cardanol with phenol in the presence of boron trifluoride afforded the 1,8-bis(hydroxyphenyl)pentadecane structure (ref. 261). Reaction then with a molar proportion of epichlorhydrin and polymerisation resulted in final products considered to be superior in properties to and cheaper than those derived from bisphenol A. The corresponding fully saturated cardbisphenol compound has been converted to a water soluble bis Mannich base by reaction with diethanolamine and formaldehyde (ref. 262) of value for cathodic electrodeposition. In another case of a related bis diethanolamine product, it was found necessary to react the hydroxyl groups with the monoisocyanate resulting from treatment of tolylenediisocyanate (TDI) with a molecular proportion of cardanol (ref. 263) in order to obtain a suitable binder for... 

Phenol can be produced directly from benzene by use of N2O as an oxidizing agent in the gas phase. Catalysts are modified ZSM-5 or ZSM-11 materials, containing elements such as antimony, arsenic, beryllium, boron, cobalt, chromium, copper, gaUium, indium, iron, nickel, scandium, vanadium or zinc. (208)... 

The goal of chemical modification of phenolics is the improvement of chemical and physical properties and to tailor the polymer to specific applications. Phenolics can be modified during synthesis by use of substituted monomers or monomer mixtures and after synthesis by electrophilic ring substitution, nucleophilic hydroxyl group capping, and reactions with compounds of boron, phosphorous, silicon, and titanium. 

The nanocomposites obtained firom phenolic resin and carboxylated MWNTs showed an improvement of the thermal stability than the neat phenolic resin. The highest thermal stability was obtained in the case of the nanocomposites obtained by in situ polymerization, due to the quality of dispersion of the functionalized MWCNTs [94]. An enhancement of the thermal stability was also obtained in the case of nanocomposites containing boron phenolic resin and MWCNTs modified with nitric acid, 4,4 -diaminodiphenyl methane and boric acid. This effect was ascribed to better interfacial interactions between modified MWCNTs and the resin matrix [95]. 

Liu, L., Ye, Z. Effects of modified multi-walled carbon nanoUrbes on the curing behavior and thermal stability of boron phenolic resin. Polym. Degrad. Stab. 94, 1972-1978 (2009)... 

Notsu H, Tatsuma T, Fujishima A (2002) Tyrosinase-modified boron-doped diammid electrodes for the determination of phenol derivatives. J Electroanal Chem 523 86-92... 

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