Poly（lactic acid）-based biocomposites were developed with hemp hurd （Cannabis sativa L.） with grafting-based interfacial compatibilization. Poly（lactic acid） was extruded with hemp hurd and glycidyl methacrylate...Poly（lactic acid）-based biocomposites were developed with hemp hurd （Cannabis sativa L.） with grafting-based interfacial compatibilization. Poly（lactic acid） was extruded with hemp hurd and glycidyl methacrylate as the polymer/hurd interfacial compatibilizer, and injection molded. Interfacial compatibility between poly（lactic acid） and hemp hurd increased with grafted glycidyl methacrylate in comparison to the non-compatibilized control, as corroborated by scanning electron microscopy fractog- raphy and mechanical analysis, which showed increases in the glycidyl methacrylate-grafted 20% （w/w） hemp hurd/poly（lactic acid） biocomposite, retaining 94% of the neat polymer strength, with increases in crystallinity, and showing a range of thermo-mechanical properties desirable for rigid biocomposite aoolications.展开更多
This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citri...This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd particleboard.Pyrolysis-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite applications.The choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the hurd.Py-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain cultivars.While FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based bio-composites.Furthermore,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual mass.The findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing modality.This assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.展开更多
以脱氢枞胺为原料,在三氟乙酸酐和乙酸酐保护其氨基后,经B环铬酸氧化转化成为(酮)N-三氟乙酰基-7-氧代脱氢枞胺(2a)和N-乙酰基-7-氧代脱氢枞胺(2b),酮再与盐酸氨基脲缩合形成(缩氨基脲)N-三氟乙酰基脱氢枞胺-7-氨基脲酰腙(3a)和N-乙酰...以脱氢枞胺为原料,在三氟乙酸酐和乙酸酐保护其氨基后,经B环铬酸氧化转化成为(酮)N-三氟乙酰基-7-氧代脱氢枞胺(2a)和N-乙酰基-7-氧代脱氢枞胺(2b),酮再与盐酸氨基脲缩合形成(缩氨基脲)N-三氟乙酰基脱氢枞胺-7-氨基脲酰腙(3a)和N-乙酰基脱氢枞胺-7-氨基脲酰腙(3b),然后在氯化亚砜的处理下发生Hurd-Mori反应,环合生成(B环并1,2,3-噻二唑衍生物)N-三氟乙酰基脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(4a)和N-乙酰基脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(4b),最后在碱性条件下水解脱去氨基保护基,合成了脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(5)。通过FT-IR、~1H NMR、^(13) C NMR和ESI-MS等方法对2a、3a、4a、4b和5的结构进行了表征,进一步分析了4a、4b和5这3种新型脱氢枞胺1,2,3-噻二唑衍生物的谱图特征及结构差异。展开更多
基金the scholarship support received from University of Southern Queenslandfinancial support from the Ningbo Natural Science Foundation (Grant No. 2013A610023)Ningbo Key Laboratory of Polymeric Materials (Grant No. 2010A22001)
文摘Poly（lactic acid）-based biocomposites were developed with hemp hurd （Cannabis sativa L.） with grafting-based interfacial compatibilization. Poly（lactic acid） was extruded with hemp hurd and glycidyl methacrylate as the polymer/hurd interfacial compatibilizer, and injection molded. Interfacial compatibility between poly（lactic acid） and hemp hurd increased with grafted glycidyl methacrylate in comparison to the non-compatibilized control, as corroborated by scanning electron microscopy fractog- raphy and mechanical analysis, which showed increases in the glycidyl methacrylate-grafted 20% （w/w） hemp hurd/poly（lactic acid） biocomposite, retaining 94% of the neat polymer strength, with increases in crystallinity, and showing a range of thermo-mechanical properties desirable for rigid biocomposite aoolications.
文摘This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting protocols.The findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd particleboard.Pyrolysis-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite applications.The choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the hurd.Py-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain cultivars.While FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based bio-composites.Furthermore,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual mass.The findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing modality.This assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.
文摘以脱氢枞胺为原料,在三氟乙酸酐和乙酸酐保护其氨基后,经B环铬酸氧化转化成为(酮)N-三氟乙酰基-7-氧代脱氢枞胺(2a)和N-乙酰基-7-氧代脱氢枞胺(2b),酮再与盐酸氨基脲缩合形成(缩氨基脲)N-三氟乙酰基脱氢枞胺-7-氨基脲酰腙(3a)和N-乙酰基脱氢枞胺-7-氨基脲酰腙(3b),然后在氯化亚砜的处理下发生Hurd-Mori反应,环合生成(B环并1,2,3-噻二唑衍生物)N-三氟乙酰基脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(4a)和N-乙酰基脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(4b),最后在碱性条件下水解脱去氨基保护基,合成了脱氢枞胺-6-烯[7,6-d]-并-1,2,3-噻二唑(5)。通过FT-IR、~1H NMR、^(13) C NMR和ESI-MS等方法对2a、3a、4a、4b和5的结构进行了表征,进一步分析了4a、4b和5这3种新型脱氢枞胺1,2,3-噻二唑衍生物的谱图特征及结构差异。
