Two series of macromolecular complexes of poly(ethylene oxide) (PEO) [100K and 600K]/sodium poly(α,l-glutamate) (PGNA) [MW 1K and 45K] and poly(ethylene glycol) [MW 350−2000]/PGNA [1K] have been prepared by solution blending using water/methanol mixtures. All the macromolecular complexes were soluble in water. The PGNA/PEO macromolecular complexes were mechanically reliable opaque films and may be stretched a couple of fold to form white opaque fibrils. Formation of the α-helical conformation of PGNA in the complexes was determined by CD studies; e.g., the CD spectrum of a film of PGNA 1K−PEO 600K (1:2.5, w/w) complex showed a positive peak at 200 nm and two negative peaks at 207 and 220 nm, indicating the presence of the α-helical PGNA conformation in the complex. FT-IR spectra of the complexes support the presence of the α-helical PGNA conformation in the macromolecular complexes. Wide-angle X-ray diffraction (WAXD) patterns of the PGNA 1K−PEO 600K (1:2.5 and 1:5, w/w) indicate that some of the PEO crystalline segments in the complex form a near planar zigzag conformation. Solution 23Na and 2D-NOESY 1H NMR spectra of the complexes in nonaqueous solvents revealed interaction between the PEO and PGNA at the following sites:  CH2−CH2 (of PEO) and γ-CH2− (of PGNA) [hydrophobic interaction] and 〉O- - -Na+ [ion−dipole interaction]. In aqueous solutions, ion−dipole complex sites dissociated completely to form free (solvated) sodium ions, and the number of contact points interacting through hydrophobic interactions was reduced significantly and diminished in dilute solutions. The proposed solid-state structure of the macromolecular complex is a helical PGNA core; PEO crystalline segments having near planar zigzag conformations; glutamate and ethylene oxide segments interacting through ion−dipole interaction; and β and γ groups of PGNA side groups interacting with PEO segments through hydrophobic interactions.

SYNOPSISThe course and kinetics of nonisothermal bulk polymerization of multifunctional acrylates were studied by dynamic differential scanning calorimetry (DSC). Measurements were carried out for four straight-chain monomers, diethylene glycol diacrylate (DEGDA), triethylene glycol diacrylate (TEGDA), tetraethylene glycol diacrylate (TTGDA), and poly(ethy1ene glyco1)diacrylate (PEGDA) (mol. wt. 600), to study the effect of the backbone chain length, atmosphere, and type of initiator on the crosslinking kinetics. 4,4'-Azobis(4-cyanovaleric acid) (1.0%, w/w) was used as a free-radical initiator. From the dynamic scanning of polymerization of DEGDA at five heating rates (2-3O0C/min), the average heat of polymerization (AH,) was found to be 524.2 J/g. An activation energy of 108.8 kJ/ mol and preexponential factor 5.34 X lo'* s-l were obtained from the Arrhenius plot, In daldt. The rate of polymerization was found manyfold greater at 20-60% conversion than at the initial stage (2-8% conversion). Polymerization was studied under both nitrogen and air atmosphere. The results corresponded well with the theory of oxygen inhibition. Different types of initiators, e.g., 4,4'-azobis(4-~yanovaleric acid) (ABCVA), 2,2'-azobisisobutyronitrile (AIBN), and benzoyl peroxide (BPO) were used for polymerization and ABCVA was found to be the most efficient among all. 0 1995 John Wiley & Sons, Inc.

Several N-acryloyl and N-methacryloyl substituted amino acids have been prepared and copolymerized with acrylic acid and itaconic acid to prepare new polyelectrolytes . Due to an acid-base reaction, mixing of the water soluble copolymers with glass powders, having leachable Ca2+, A13+, etc., type cations, produces inorganic-organic composites hardened by salt -bridge formation. These heretofore unexplored polyelectrolytes are shown to be very useful for preparing improved dental biomaterials.

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