Phenolic polymers properties

Singh K P and Palmese G R (2004), Enhancement of phenolic polymer properties by use of ethylene glycol as diluent , J Appl Polym Sci, 91, 3096-3106. 

W. Knop and A. Scheib, Chemistry and Applications of Phenolic Resins-Polymer Properties and Applications, Springer-Verlag, Berlin (1979). 

Network properties and microscopic structures of various epoxy resins cross-linked by phenolic novolacs were investigated by Suzuki et al.97 Positron annihilation spectroscopy (PAS) was utilized to characterize intermolecular spacing of networks and the results were compared to bulk polymer properties. The lifetimes (t3) and intensities (/3) of the active species (positronium ions) correspond to volume and number of holes which constitute the free volume in the network. Networks cured with flexible epoxies had more holes throughout the temperature range, and the space increased with temperature increases. Glass transition temperatures and thermal expansion coefficients (a) were calculated from plots of t3 versus temperature. The Tgs and thermal expansion coefficients obtained from PAS were lower titan those obtained from thermomechanical analysis. These differences were attributed to micro-Brownian motions determined by PAS versus macroscopic polymer properties determined by thermomechanical analysis. 

Phenol-formaldehyde resins using prepolymers such as novolaks and resols are widely used in industrial fields. These resins show excellent toughness and thermal-resistant properties, but the general concern over the toxicity of formaldehyde has resulted in limitations on their preparation and use. Therefore, an alternative process for the synthesis of phenolic polymers avoiding the use of formaldehyde is strongly desired. 

In addition to acting as a crosslinking site, the hydroxymethyl group and unsubslituled o and p positions may be used as reactive sites to join numerous other compounds to the phenolic polymer, These modified resins often possess many properties normally not attributable tn phenolics in the unaltered slate. 

Many of the applications in which CEs are involved require clarity or uniform properties on a microscopic structural level, so miscibility or molecular-scale mixing is important when CE-based blends are formed. There are some examples of miscible or homogeneous CE blends with vinyl polymers. One interesting class of these is a mixture of CE and poly(vinyl phenol) (PVPh) [101,102], This phenolic polymer is known to form a miscible blend with a wide variety of polymers with potential hydrogen-bond-accepting groups [101], the latter set including commercially available CEs, i.e., cel-... 

Madders. Phenolic polymers are known to have high rigidity, and this property extends to phenolic foams, which are highly friable. In order to reduce friabUity and permit some flexibUity and toughness, various kinds of modifiers are sometimes used. Reactive modifiers are used in the course of resol-resin preparation, and they become integral parts of the polymer structure. Examples include PVA (polyvinyl alcohol), PVA-PVC (polyvinyl alcohol-polyvinyl chloride-copolymer), resorcinol, o-cresol, furfuryl alcohol, and other various types of polyols. 

Knop W, Scheib A (1979) Chemistry and applications of phenolic resins-polymer properties... 

Tyloxapol, 4-11,1,3,3-Teiramethytbutyl)phenol polymer with formaldehyde and oxirane oxyethylated tertiary octylphenol formaldehyde polymer oxyethylated tertiary octyl phenol-poly methylene polymer p-isooctylpolyoxyeth-y ten e phenol formaldehyde polymer tyloxypal Aleva ire Superinone Triton A-20 Triton WR-1339. Nonionic detergent with surface-ten si on-reducing properties. Prepn Bock, Rainey, U.S. pat. 2.454,541 (1948 to Rohm Haas) Cornforth et at.. Nature 168, 150 (19SI). 

The effects that initiator derived residues and functional groups have on polymer properties is an area that needs further study. For example, as discussed above, benzoyl peroxide leads to the formation of benzoyloxyphenyl groups in PS. It is known that the polymerization of p-benzoyloxystyrene [155] and its copolymerization with styrene [156] leads to the formation of photo-reactive polymers. Upon irradiation these polymers undergo a facile photo-Fries Rearrangement resulting in the conversion of the benzoyloxyphenyl groups to hydroxybenzophenone moieties [157]. Other side reactions also lead to the formation of phenolic groups and free benzoyloxy radicals [155]. 

Synonyms Formaldehyde, phenol polymer Formaldehyde, polymer with paraformaldehyde and phenol Paraformaldehyde, formaldehyde, phenol polymer Paraformaldehyde, phenol polymer Phenol-formaldehyde copolymer Phenol, formaldehyde polymer Phenol, polymer with formaldehyde Phenol, polymer with paraformaldehyde Classification Thermosetting polymer Definition Reaction prod, of phenol with aq. 37-50% formaldehyde with basic catalyst chief class of phenolic resin Formula (CeHeO (CH20)x)x Properties Gray to bik., hard, infusible solid when cured resist, to moisture, soivs., heat to 200 C dimensionally stable good elec, resist. noncombustible... 

This methodology is quite general and can be utilized to prepare several types of polymers such as polyamides, polyimides, polyurethanes, polyethers etc. The polymer properties depend on the type of functional groups that link the polymer building blocks. Further modulation is achievable by varying the nature of the difimctional monomer within each class of polymers. It is not always necessary to condense two difunctional monomers. Some polymers such as polyethers are prepared by the oxidative coupling of the corresponding phenols. A few examples of polymers that can be prepared by the condensation reactions are shown in Fig. 1.2. 

Phenolic polymers in many respects are ideal for microlithographic resists as they provide predictable, well-controlled dissolution behavior, excellent adhesion properties, and acceptable plasma etch resistance. But the strong absorption of phenolic polymers at 193 nm (illustrated in Fig. 8) precludes their use at that wavelength, and 193-nm resist efforts can be characterized as the pursuit of new transparent polymer systems that combine these three functional attributes as effectively as do their phenolic counterparts. 

Megiatto J D, Silva C G, Rosa D S and Frollini E (2008), Sisal chemically modified with lignins Correlation between fibers and phenolic composites properties , Polym Degrad Stab, 93(6), 1109-1121. 

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