Formation, structure and physical properties of intermacromolecular complexes through hydrogen bonding

Abstract

In part A, the solid of the complex between poly (acrylic acid) (PAA) and poly(ethylene oxide)(PEO), and that betweenply(methacrylic acid)(PMAA) and PEO formed via hydrogen bonding was studied by differential-scanning calorimeter(DSC) and by Fourier-transform infrared(FTIR) spectroscopic measurements. Melting temperature $T_m$ and the degree of the crystallinity $X_c$ of PEO in the systems PAA (or PMAA)/PEO blends obtained from aqueous or dimethyl sulfoxide(DMSO) medium were measured in various mol \% of PEO. It was found that 50 mol \% of PEO is a critical composition, which gives a new evidence for 1:1 complex formation between PAA(or PMAA) and PEO. From the FTIR spectroscopic analysis in conjunction with DSC measurements we also found that the effects of solvent and of hydrophobic interaction (due to the -methyl group of PMAA) are the important factors also affect the crystallization behavior and the microstructure of the PAA(or PMAA)/PEO blend in solid state. In part B, interpolymer complex formation between poly(L-proline)(PLP) with helical structure and PMAA with random-coiled structure through hydrogen bonding in aqueous medium has been studied by several experimental techniques, e.g. viscosity, turbidimetry, potentiometry, conductometry, sacanning electron microscopy, and X-ray diffraction measurements. The descreases in reduced viscosity with increasing quantity of PLP into a constant amount of PMAA reveals the formation of complex between PLP and PMAA. The minimum in reduced viscosity at [PLP]/[PMAA]=1.0 suggests 1:1 complex formation. A distinct change of slope at [PLP]/[PMAA] in curves for turbidity, pH, and conductance supports this conclusion. A scanning electron micrograph for PLP-PMAA 1:1 complexes shows that the the PLP-PMAA complexes has the shape of entangled long fibers. A X-ray diffraction curve for the PLPPMAA complexes gives no diffraction patterns, indicating the destruction of helical structure of PLP interpolymer complexation with PMAA...