An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in th...An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm) and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1 mm) after burying in soil for 36 days.展开更多
It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. se...It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. self-condensation in aprotic polar solvent occurs to give symmnetrical disubstituted diphenyl ethers. However. when it is substituted with moderate electron withdrawing groups, no diphenyl ethers are obtained under the same conditions, instead, corresponding carboxylates are yielded. As a result. the applicability of this reaction is distinctly clarified展开更多
文摘An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm) and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1 mm) after burying in soil for 36 days.
文摘It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. self-condensation in aprotic polar solvent occurs to give symmnetrical disubstituted diphenyl ethers. However. when it is substituted with moderate electron withdrawing groups, no diphenyl ethers are obtained under the same conditions, instead, corresponding carboxylates are yielded. As a result. the applicability of this reaction is distinctly clarified
