Abstract
The miscibility, and molecular interaction within novolactype phenolic resin blended various thermoplastic resin(i.e.phenoxy, poly adipic ester, and poly ethylene oxide)wereinvestigated. Differential scanning calorimetry (DSC), solidstate magnetic nuclear resonance (NMR)and Painter-ColemanAssociation Model(PCAM) were used to study the miscibility,thermodynamic properties and the molecular motion of phenolicblends. All the thermoplastic resin are miscible with novolactype phenolic resin, due to strong intermolecular hydrogenbonding present in the phenolic blend. The Gibbs freefreeenergies of various phenolic blends are negative through thewhole blend compositionsthat simulated from the PCAM model. Theorder of intermolecular hydrogen bonding strengthis phenolic/phenoxy, phenolic/poly adipic ester, and then phenolic/PEOblend. In other word,the hydrogen bonding strength of hydroxyl-hydroxyl is the strongth, carbonyl-carbonyl is the second, anthe ether-hydroxyl is the weakest on in this blend system. Thephase separationn would occur when the London dispersin forcedominates over the hydrogen bondingat higher temperature inphenolic blends. The order of phase separation temperature isPEO,poly adipic ester, and then phenoxy while the degradatintemperature is not consideredin this blend system. The enthalpicterm causes the phase separation is weightout thanthe entropicterm at higher temperature for phenolic blend. The glasstransition temperature of phenolic blend was dependent on themodifierstructure, as well as the average strength of hydrogenbonding of polymer blend. In the phenolic/PEO blend, the averagestrength of hydrogen bonding of phenolic blend increasedthatresults in the positive derivation of glass transitiontemperature. On the contrary,in the phenolic/phenoxy andphenolic/poly adipic ester blend system, the descreasingofaverage of hydrogen bonding leads to the negative derivationof glass transition temperature. The miscible modifier wouldhinder the self-association of phenolic, and forms theintermolecular hydrogen bonding. When the intermolecularhydrogen bondingcan compensate the loss of self-association ofphenolic, that resulting in a positivederivation of glasstransition temperature. The solid state NMR is used to studythe molecular motion and miscibility of phenolicblend, which isdependent on the free volume of phenolic blend. In the phenolic/phenoxyblend, the excess free volume of polymer blend ispositive. In the phenolic/PEO, due to the phenolic interactswith flexible thermoplastic chain, the molecular motionofphenolic is still increased when the excess free volune isnegative. The solid stateNMR (i.e. chemical shift, T1r timerelaxation. T1 relaxation time dispersion, and efficiency ofcross polarization) can interpret all of the molecular motion ofphenolic blend. When phenolic was added to the thermoplasticresin the crystallinity of PEO and poly adipic ester will bedecreased, and the crystalline would be destroyed completely.Thedegree of the decreasing of crystalline is dependent on thecrystallizatin polentialof thermoplastic reisn and also on thestrength of intermolecular hydrogen bonding. ThePEO exhibits thehighest crystallization and the lowest intermolecular hydrogenbondingwith phenolic, it need the most amount of phenolic todestroy the crystalline of PEO in the blend s