Phenolics Polymer blends

The most commonly used stabilizers are barium, cadmium, zinc, calcium and cobalt salts of stearic acid phosphorous acid esters epoxy compounds and phenol derivatives. Using stabilizers can improve the heat and UV light resistance of the polymer blends, but these are only two aspects. The processing temperature, time, and the blending equipment also have effects on the stability of the products. The same raw materials and compositions with different blending methods resulted in products with different heat stabilities. Therefore, a thorough search for the optimal processing conditions must be done in conjunction with a search for the best composition to get the best results. 

Blends of enzymatically synthesized poly(bisphenol-A) and poly(p-r-butylphenol) with poly(e-CL) were examined. FT-IR analysis showed the expected strong intermolecular hydrogen-bonding interaction between the phenolic polymer with poly(e-CL). A single 7 was observed for the blend, and the value increased as a function of the polymer content, indicating their good miscibility in the amorphous state. In the blend of enzymatically synthesized poly(4,4 -oxybisphenol) with poly(e-CL), both polymers were miscible in the amorphous phase also. The crystallinity of poly(e-CL) decreased by poly(4,4 -oxybisphenol). 

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-... 

In order to control the pore texture in carbon materials, blending of two kinds of carbon precursors, the one giving a relatively high carbonization yield and the other having a very low yield, was proposed and called polymer blend method [112], This idea gave certain success to prepare macroporous carbons from poly(urethane-imide) films prepared by blending poly(amide acid) and phenol-terminated polyurethane prepolymers [113]. By coupling this polymer blend method with... 

Keywords. Cyanate ester, Polycyanurates, Phenolic-triazine, Polymer matrix composite, Cure kinetics, Polymer blends, Cyanate-epoxy blend, Bismaleimide-triazine resins, Aerospace structure... 

Poly(4-vinyl phenol) with PVAc, EVAc, PCL, PPL, PMA, PEA, PBA, The amount of free and bonded C=0 vibrations were determined fort the PVPh/hydrogen bonding polymer blends, using a curve fitting procedure Coleman et al., 1989... 

In this section, the future developments will be discussed that might be expected in commercial polymer blends comprising at least one of the constituents from the class of commodity polymers. Generally, the commodity polymers considered include polyethylene (and variants LDPE, HOPE, LLDPE, VLDPE and ethylene copolymers), polypropylene (PP), ethylene-propylene rubber (EPR and EPDM), polyvinylchloride (PVC), polystyrene (PS), ABS, and poly(methyl methacrylate) (PMMA). Elastomeric polymers commonly used in tire and associated applications are important in polymer blends as many tire component constructions employ polymer blends to maximize performance. However, these will not be considered here. Thermosetting polymers which could be classified as commodity polymers (urethane, phenolics, epoxies) will also not be covered, but will be mentioned in a later section discussing new polymer blends designed for specific applications (e.g., water based coatings). 

Cheng, K. K. T.C. Hsu, and L.H. Kao, A microscopic view of chemically activated amorphous carbon nanofibers prepared from core/sheath melt-spiiming of phenol formaldehyde-based polymer blends. J. Mater. Sci. 2011,46(11), 3914-3922. 

The flammability behavior of some polymer blends is summarized in Table 6.7. Here one can also obtain some useful information thus, if the material burns readily while melting slowly and emits a deflnite paraffinic odor, these point to a polyolefin blend. Highly sooty flames are a deflnite indication that aromatic structures are present, while the odor of burnt horn indicates nitrogen-containing components. The identification of PVC in blends is relatively easy because generally a stinging smell of hydrochloric acid develops while the material usually burns very poorly. When polycarbonates are present in the blend, a typical odor of phenol is noticed in most cases. 

Coleman, M. M., Pehlert, G. J., Yang, X., Stallman, J. B., and Painter, P. C. 1996. Self-association versus interassociation in hydrogen bonded polymer blends 1. Determination of equilibrium constants from miscible p)oly(2,6-dialkyl-4-vinyl phenol) blends. Polymer 37 4753-4761. 

Another miscible semicrystalline polymer/amorphous polymer blend SMP is a polyethylene oxide (PEO)/novolac-type phenolic resin blend [24]. The blend was found to be completely miscible in the amorphous phase when the phenolic content is up to 30 wt%, and the crystalline melting temperature (T,f) of the PEO phase working as a transition temperature can be tuned. 

Ratna, D., Abraham, T. N., and Karger-Kocsis, J. 2008. Studies on polyethylene oxide and phenolic resin blends. Journal of Applied Polymer Science 108 2156-2162. 

Another interest of irradiation in the field of the conductivity of polymer blends was shown by Faez etal. These authors incorporated EPDM to lANl in order to improve mechanical properties of the material. PANl was doped not with irradiation, but with dodecylbenzene sulfonic acid by reactive processing in an internal blender. To cross-link the EPDM, a phenolic resin and e-beam irradation (75 and 150 kGy) were compared. Contrary to the cross-linking by phenolic resin, the cross-linking by e-beam irradiation did not interfere with the presence of the acid necessary for doping PANl. Consequently, better mechanical properties were obtained. Moreover, irradiation-induced additional conductivity led to a slightly more conductive material. 

Specific interactions in binary blends of ethylene-vinyl acetate copolymer with various low molecular weight terpene-phenol tackifying resins (TPR) were systematically investigated, as a function of the composition of the blend and of the electron acceptor ability of the resin, by using attenuated total reflection FTIR spectroscopy. Molecular acid-base were evidenced between TPR hydroxyl groups and EVA carbonyl groups. Quantitative information on the fraction of acid-base bonded entities, the enthalpy and equilibrium constant of pair formation were obtained. A crystalline transition of the EVA copolymer was observed and discussed in terms of enthalpy and entropy considerations based on FTIR and calorimetric DSC investigations. Fundamental results are then summarised to predict the interfacial reactivity of such polymer blends towards acid or basic substrates. 16 refs. 

Phenolics can be chemically modified during synthesis by the use of substituted monomers or monomer mixtures. After synthesis additional modification can occur by electrophilic ring substitution, nucleophilic hydro l group capping, and reactions with compounds of boron, phosf orous, silicon, and titanium. Furthermore, phenolics can be physical modified by formation of polymer blends, interpenetrating polymer networks, and foam or by using fibers, fillers or other additives. 

SiC nanofibers by melt-spinning of polymer blends have been prepared from PCS as a SiC ceramic precursor and a novolac-type phenol-formaldehyde resin [121]. These nanofibers were amorphous, about 100 nm in diameter, more than 100 (un long, and were rich in oxygen. 

Polymer Blends. A number of polymers are mentioned as modifiers for epoxy resins. Coal tar, phenol-formaldehyde, and polyurethane combine readily to produce intermediate properties. Silicones can add more unique properties. Polyesters and melamine-formaldehyde are also mentioned in the literature. 

Chemical re-stabilization of recycled material against the thermal- and light-induced degradation is essential. Addition of 0.1-0.5 wt% of a sterically hindered phenol and a phosphite at a ratio varying from 10 1 to 1 10 is recommended (Pauquet et al. 1994). For outdoor applications, hindered amine light stabilizers with UV absorbers of the benzotriazole type are to be used (Herbst et al. 1995, 1998). Examples of blends used for polymer recycling are listed in Table 1.80. For more details, see Chap. 20, Recycling Polymer Blends in this book. 

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