Poly(4-vinylphenol) (PVPh) was blended with four different polymers: poly(vinyl methyl ether) (PVME), poly(vinyl acetate) (PVAc), poly(2-vinylpyridine) (P2VP), and poly(4-vinylpyridine) (P4VP) by solvent casting. The miscibility of these four PVPh-based blend systems was investigated using differential scanning calorimetry (DSC) and the composition-dependent glass transition temperature (Tg) was predicted by a thermodynamic theory. The hydrogen bonds between phenolic group in PVPh and ether group, carbonyl group or pyridine group was confirmed by Fourier transform infrared (FTIR) spectroscopy. The fraction of hydrogen bonds was calculated by the Coleman-Graf-Painter association model. Linear dynamic viscoelasticity of four PVPh-based miscible polymer blends with hydrogen bonding was investigated. Emphasis was placed on investigating how the linear dynamic viscoelasticity of miscible polymer blends with specific interaction might be different from that of miscible polymer blends without specific interaction. We have found that an application of time-temperature superposition (TTS) to the PVPh-based miscible blends with intermolecular hydrogen bonding is warranted even when the difference in the component glass transition temperatures is as large as about 200 °C, while TTS fails for miscible polymer blends without specific interactions. On the basis of such an observation, we have concluded that hydrogen bonding suppressed concentration fluctuations in PVPh-based miscible blends. It has been found that both the intra-association (self-association) of the phenoxy hydroxyl groups in PVPh and inter-association (intermolecular interactions) between the constituent components have a profound influence on the frequency dependence of dynamic moduli in the terminal region of the PVPh-based miscible blend systems investigated.
Hydrogenated functional polynorbornenes (HFPNBs) were synthesized and they were used to investigate the miscibility and rheology of HFPNB-based miscible blends with hydrogen bonding. Specifically, functional norbornenes with carboxylic (-COOH) group or hydroxyl (-OH) group were first synthesized and then they were polymerized, via ring-opening metathesis polymerization followed by hydrogenation, to obtain HFPNBs, HPNBCOOH and HPNBOH. Subsequently, the miscibility of binary blends consisting of (1) HPBNCOOH and polycarbonate (PC), (2) HPBNCOOH and poly(2-vinylpyridine) (P2VP), and (3) HPBNOH and PC was investigated using DSC and FTIR spectroscopy. It has been found that both PC/HPBNCOOH and P2VP/HPBNCOOH blend systems exhibit a broad, single glass transition over the entire blend compositions as determined by DSC, indicating that the respective blend systems are miscible, and they form hydrogen bonds as determined by FTIR spectroscopy. On the other hand, PC/HPBNOH blends were found to exhibit two glass transition temperatures, indicating that the blends are not miscible. The dynamic oscillatory shear rheometry has shown that reduced log G' versus log aTω and log G" versus log aTω plots, and also log G' versus log G" plots of PC/HPBNCOOH and P2VP/HPBNCOOH blend systems are independent of temperature. We have concluded that an application of TTS to the miscible polymer blends with hydrogen bonding is warranted although the difference in component glass transition temperatures is as large as 91 °C for the PC/HPNBCOOH blend system.