In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration ...In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration and the phase transition of PBA,we performed two-dimensional(2D)correlation analysis.We found thatβ-form PBA crystal undergoes not only the melting process but also crystal transition upon the heating process.展开更多
The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this w...The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this work aimed to study the effect of adding nanocellulose (nCE) with 1, 3, and 5 wt.% on poly(butylene adipate-co-butylene terephthalate) (PBAT). Thermal, structural, relaxometric, and rheological assessments were carried out. Quantitative evaluation of PBAT copolymer by high field NMR revealed 56.4 and 43.6 m.% of the butylene adipate and butylene terephthalate segments, respectively. WAXD measurement on the deconvoluted diffraction patterns identified that nCE was a mixing of Cellulose I and Cellulose II polymorph structures. At any composition, nanocellulose interfered with the PBAT crystallisation process. Also, a series of new PBAT crystallographic planes appeared as a function of nanocellulose content. PBAT hydrogen molecular relaxation varied randomly with nanocellulose content and had a strong effect on the hydrogen relaxation. PBAT cold crystallisation and melting temperatures (T<sub>cc</sub> and T<sub>m</sub>) were almost unchangeable. Although T<sub>cc</sub> did not change during polymer solidification from PBAT molten state, the sample’s degree of crystallinity varied with composition through the transcrystallization phenomenon. Nanocomposite thermal stability decreased possibly owing to the catalytic action of sulfonated amorphous cellulose chains. For the sample with 3 wt.% of nanocellulose, the highest values of complex viscosity and storage modulus were achieved.展开更多
Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling ...Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling reactive distillation tower （BRDT） at atmospheric pressure. In this new type of reactor, direct esterification between ethylene glycol and adipic acid was accomplished efficiently and rapidly. A bench BRDT with the height of 2 m was applied for the esteriflcation process of l^oly （ethylene adlpate） （P＇EA）. In the continuous operation, Hn- ear oligomers were discharged from the bottom of the column, while water passed a few column trays and a pack- ing section as a condensation byproduct. The influence of major operating conditions on reactor performance was also simulated. Simulation results were in good agreement with experimental data, providing a strategy for devel- oping and optimizing this process.展开更多
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
文摘In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration and the phase transition of PBA,we performed two-dimensional(2D)correlation analysis.We found thatβ-form PBA crystal undergoes not only the melting process but also crystal transition upon the heating process.
文摘The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this work aimed to study the effect of adding nanocellulose (nCE) with 1, 3, and 5 wt.% on poly(butylene adipate-co-butylene terephthalate) (PBAT). Thermal, structural, relaxometric, and rheological assessments were carried out. Quantitative evaluation of PBAT copolymer by high field NMR revealed 56.4 and 43.6 m.% of the butylene adipate and butylene terephthalate segments, respectively. WAXD measurement on the deconvoluted diffraction patterns identified that nCE was a mixing of Cellulose I and Cellulose II polymorph structures. At any composition, nanocellulose interfered with the PBAT crystallisation process. Also, a series of new PBAT crystallographic planes appeared as a function of nanocellulose content. PBAT hydrogen molecular relaxation varied randomly with nanocellulose content and had a strong effect on the hydrogen relaxation. PBAT cold crystallisation and melting temperatures (T<sub>cc</sub> and T<sub>m</sub>) were almost unchangeable. Although T<sub>cc</sub> did not change during polymer solidification from PBAT molten state, the sample’s degree of crystallinity varied with composition through the transcrystallization phenomenon. Nanocomposite thermal stability decreased possibly owing to the catalytic action of sulfonated amorphous cellulose chains. For the sample with 3 wt.% of nanocellulose, the highest values of complex viscosity and storage modulus were achieved.
基金Supported by the National Natural Science Foundation of China （21176070）.
文摘Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the con- tinuous esterification process of polyester polyols was developed, which was carried out in an innovational bub- bling reactive distillation tower （BRDT） at atmospheric pressure. In this new type of reactor, direct esterification between ethylene glycol and adipic acid was accomplished efficiently and rapidly. A bench BRDT with the height of 2 m was applied for the esteriflcation process of l^oly （ethylene adlpate） （P＇EA）. In the continuous operation, Hn- ear oligomers were discharged from the bottom of the column, while water passed a few column trays and a pack- ing section as a condensation byproduct. The influence of major operating conditions on reactor performance was also simulated. Simulation results were in good agreement with experimental data, providing a strategy for devel- oping and optimizing this process.
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.
