Thermophilic actinomycetes were isolated from sediment of the Chingshuei hot spring in north Taiwan, and the strain HS 45-1 was selected from colonies which formed distinct clear zones on agar plate with emulsified polyethylene succinate (PES). The film of PES disappeared within 6 days in liquid cultures at 50°C. The strain HS 45-1 was also able to degrade poly (-carpolactone) (PCL) and poly (3-hydroxybutyrate) (PHB) films completely within 6 days in liquid cultures. Basing on the results of phynotypic characteristics, phylogenetic studies and DNA-DNA hybridization, strain HS 45-1 should be assigned to Micorbispora rosea subsp. taiwanensis.
Two phosphonate-containing bismaleimide (BMI) [(4,4Ј-bismaleimidophenyl)phosphonate] monomers with different melting temperatures and similar curing temperatures were synthesized by reacting N-hydroxyphenylmaleimide with two kinds of dichloride-terminated phosphonic monomers. The BMI monomers synthesized were identified with 1 H-, 13 C-, and 31 P-nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The phosphonate-containing BMI monomers react with a freeradical initiator to prepare phosphonate-containing BMI polymers and also with various aromatic diamines to prepare a series of polyaspartimides as reactive flame retardants. The polymerization degrees of polyaspartimides depend on the alkalinity and nucleophility of diamines as chain extenders. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were used to study the thermal properties of the phosphonate-containing BMI resins such as the melting temperature, curing temperature, glass transition temperature (T g ), and thermal resistance. All the phosphonatecontaining BMI resins, except the BMI polymers, have a T g in the range of 210 -256°C and show 5% weight loss temperatures (T 5% ) of 329 -434 and 310 -388°C in air and nitrogen atmospheres, respectively. The higher heat resistance of cured BMI resin relative to the BMI polymer is due to its higher crosslinking density. Since the recrosslinking reactions of BMI polymers and polyaspartimides occur more easily in an oxidation environment, their thermal stabilities in air are higher than are those in nitrogen gas. In addition, the thermal decomposition properties of polyaspartimides depend on the structures and compositions of both the diamine segments and the BMI segments.
A series of fluorine-containing bismaleimide (FBMI) monomers are synthesized by a 3-step reaction for using as the applications of low-k materials. The synthesized FBMI monomers are characterized by the 1 H, 13 C, 19 F nuclear magnetic resonance (NMR) spectroscopy and element analysis. These FBMI monomers react with free radical initiator or self-cure to prepare FBMI-polymers. All the self-curing FBMI resins have the glass transition temperatures (T g ) in the range of 128-141 C and show the 5% weight loss temperatures (T 5% ) of 235-293 C in nitrogen atmosphere. The higher heat resistance of selfcuring FBMI resin relative to FBMI-homopolymer is due to its higher crosslinking density. The FBMI resins exhibit improved dielectric properties as compared with commercial bismaleimide (BMI) resins with the dielectric constants (D k ) lower than 2.49, which is related to the low polarizability of the CAF bond and the large free volume of CF 3 groups in the polymers. Besides, the flame retardancy of all these FBMI resins could be enhanced via the introduction of Br-atom.
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