Poly(D,L‐lactide‐co‐glycolide) samples with different glycolide contents, ie 85:15, 75:25 and 50:50 mole ratios of lactide to glycolide, and poly(L‐lactide) were obtained from a commercial source. Polymer films of 15 µm thickness were prepared by a solvent‐casting method. Degradation studies were conducted at 37 °C in pH 7.4 phosphate buffered saline and in bovine serum albumin solution. The degradation behaviour of the films was followed by UV and FTIR spectrophotometry and viscometric and gravimetric measurements. Spectroscopic investigations showed that during the first month of degradation, both the chain length and the chain chemical structure changed, especially in the presence of bovine serum albumin. The short chains are attributed to the formation of new ester groups; however, the end‐groups may be aldehyde‐ or ketone‐like structures. While the intrinsic viscosities of all polymers decreased continuously after being exposed to the degradation media, insignificant mass loss occurred during the experimental investigation. © 2000 Society of Chemical Industry

No abstract

No abstract

No abstract

The preparation of new poly(urethaneimide)s (PUIs) having acceptable thermal stability and higher flame resistance was aimed. Two new aromatic diisocyanate-containing methyldiphenylphosphine oxide and triphenylphosphine oxide moieties were synthesized via Curtius rearrangement in situ and polymerized by various prepared diols. Four aliphatic hydroxy terminated aromatic based diols were synthesized by the reaction between ethylene carbonate and various diphenolic substances. Chemical structures of monomers and polymers were characterized by FTIR, 1 H NMR, 13 C NMR, and 31 P NMR spectroscopy. Thermal stabilities and decomposition behaviors of the PUIs were tested by DSC and TGA. Thermal measurements indicate that the polymers have high thermal stability and produce high char. Polymers exhibit quite high fire resistance, evaluated by fire test UL-94. The films of the polymers were prepared by casting the solution. Inherent viscosities, solubilities, and water absorbtion behaviors of the polymers were reported in. V

No abstract

Poly-β-alanine (PBA) and poly(3-hydroxypropionate) (PHP) were synthesized via base-catalyzed hydrogen transfer polymerization (HTP) of acrylamide and acrylic acid, respectively. Blends of PBA/PHP with different composition (PHP content, 5% to 75%) were studied using FTIR, DSC, TGA, XRD and polarized optical microscope to reveal both miscibility and thermal degradation kinetics of PBA/PHP blends. Optical images of blends were transparent and entirely uniform. Characteristic FTIR bands of both components shifted in higher frequencies with increasing fraction of another component. Melting temperature (Tm), thermal decomposition temperatures (Td), and enthalpy of fusion (ΔHf) of PHP decreased with increasing PBA fraction in blends. Thermal degradation kinetics of both components were studied by Freeman-Carroll method. Activation energies of thermal degradations of blend components were determined with good regression coefficients (at least 0.994). Activation energies of decomposition decreased from 224.14 to 86.125 kJmol -1 with increasing PHP content. XRD spectra of blends exhibited lower peak intensities than those of neat polymers. The spectroscopic, thermal, and optical methods revealed that PBA and PHP were miscible with a good compatibility in amorphous phase.

ABSTRACT:The title monomer was synthesized from 3-isopropenyl-␣,␣-dimethylbenzyl isocyanate in a significantly better yield than was previously reported. 3-Isopropenyl-␣,␣-dimethylbenzylamine proved incapable of homopolymerization using free-radical initiation but readily copolymerized with a variety of commonly available monomers under free-radical conditions. Films of some of the copolymers were prepared and crosslinked using a variety of multifunctional epoxy compounds. The films had good solvent resistance, high hardness, and good gloss.