The present study aimed to understand the effect of dielectric barrier discharge cold plasma(DBD-CP)technology on the antimicrobial chitosan deposition and the properties enhancement of polylactic acid(PLA)films.The r...The present study aimed to understand the effect of dielectric barrier discharge cold plasma(DBD-CP)technology on the antimicrobial chitosan deposition and the properties enhancement of polylactic acid(PLA)films.The results indicated that DBD-CP was an effective method for improving the adhesion and surface hydrophilicity of PLA,facilitating the deposition of chitosan coating.This modification was attributed to the increased surface roughness,as well as the presence of polar functional groups observed through atomic force microscopy,surface free energy and Fourier transform infrared spectroscopy analysis.The study further revealed that both water resistance and mechanical properties were significantly improved after DBD-CP treatment,which was positively correlated with the amount of chitosan deposited on the PLA surfaces.Following comprehensive evaluation,the treatment at 75 W was determined as the optimal condition for enhancing the properties.Additionally,the modified film exhibited strong antimicrobial activity against Staphylococcus aureus.Consequently,the DBD-CP technology could be a promising tool for better utilization of PLA-based materials in the antibacterial food packaging industry.展开更多
The menstrual cycle is always considered as a big nightmare by many women. This research aims to make this process smooth and safe by developing natural sanitary pads which are used to absorb and retain menstrual bloo...The menstrual cycle is always considered as a big nightmare by many women. This research aims to make this process smooth and safe by developing natural sanitary pads which are used to absorb and retain menstrual blood from the body. Some existing sanitary pads contain 90% plastics made of non-woven polypropylene/polyethylene sheets, super absorbent polymers, and polyethylene back sheets that will take up to 600 - 800 years to decompose. So, biodegradable sanitary pads using natural fibers are the best alternative to eliminate the pads which contain non-biodegradable materials. In this research, nonwoven bamboo will be used as the top layer, nonwoven cotton will be used as the second layer, the absorbent core is to be made by the combination of kenaf and chitosan fibers as the third layer, cotton as the fourth layer, and cornstarch-based bioplastic sheets as the bottom layer. These biodegradable natural materials will change the menstrual process into a healthy one as well as create a robust ecological community.展开更多
为改善聚乳酸的阻燃性能,利用植酸改性壳聚糖(PAMC)与三聚氰胺磷酸盐(MPP)复配得到一种新型膨胀型阻燃剂(IFR)体系,并将有机蒙脱土(OMMT)作为协效剂,通过熔融共混法制备阻燃聚乳酸(PLA)复合材料(PLA/PAMC/MPP/OMMT)。通过极限氧指数(LOI...为改善聚乳酸的阻燃性能,利用植酸改性壳聚糖(PAMC)与三聚氰胺磷酸盐(MPP)复配得到一种新型膨胀型阻燃剂(IFR)体系,并将有机蒙脱土(OMMT)作为协效剂,通过熔融共混法制备阻燃聚乳酸(PLA)复合材料(PLA/PAMC/MPP/OMMT)。通过极限氧指数(LOI)、锥形燃烧量热(CONE)测试、垂直燃烧法(UL-94)和热重分析(TGA)测试分析复合材料的阻燃性能、燃烧性能和热稳定性能。采用扫描电镜(SEM)和X-射线光电子能谱(XPS)对复合材料的炭渣进行分析,研究了OMMT与PAMC/MPP在PLA复合材料中的阻燃协效作用。结果表明:与纯PLA相比,添加质量分数为25%的PAMC/MPP后,PLA2的LOI值、UL-94等级和800℃时的残炭量分别由21、NR和0.61%增至27.5、V-1级和17.28%,HRR曲线的峰值(PHRR)和总热释放量(THR)值分别由533.5 k W/m^2和81.7 MJ/m^2下降至270.2 k W/m^2和63.7 MJ/m^2。当添加质量分数为0.5%的OMMT后,PLA3的LOI值和残炭量继续增加至30.0和18.58%,PHRR和THR值进一步下降至251.6 k W/m^2和60.6 MJ/m^2,UL-94等级达到V-0级,且熔融滴落现象消失。OMMT与PAMC/MPP之间存在较好的协同效应,可有效改善PLA复合材料的阻燃性能,本研究结果可为制备绿色阻燃PLA复合材料提供理论依据。展开更多
基金This work was financially assisted by the National Natural Science Foundation of China(32101875)China Postdoctoral Science Foundation(2021M702458).
文摘The present study aimed to understand the effect of dielectric barrier discharge cold plasma(DBD-CP)technology on the antimicrobial chitosan deposition and the properties enhancement of polylactic acid(PLA)films.The results indicated that DBD-CP was an effective method for improving the adhesion and surface hydrophilicity of PLA,facilitating the deposition of chitosan coating.This modification was attributed to the increased surface roughness,as well as the presence of polar functional groups observed through atomic force microscopy,surface free energy and Fourier transform infrared spectroscopy analysis.The study further revealed that both water resistance and mechanical properties were significantly improved after DBD-CP treatment,which was positively correlated with the amount of chitosan deposited on the PLA surfaces.Following comprehensive evaluation,the treatment at 75 W was determined as the optimal condition for enhancing the properties.Additionally,the modified film exhibited strong antimicrobial activity against Staphylococcus aureus.Consequently,the DBD-CP technology could be a promising tool for better utilization of PLA-based materials in the antibacterial food packaging industry.
文摘The menstrual cycle is always considered as a big nightmare by many women. This research aims to make this process smooth and safe by developing natural sanitary pads which are used to absorb and retain menstrual blood from the body. Some existing sanitary pads contain 90% plastics made of non-woven polypropylene/polyethylene sheets, super absorbent polymers, and polyethylene back sheets that will take up to 600 - 800 years to decompose. So, biodegradable sanitary pads using natural fibers are the best alternative to eliminate the pads which contain non-biodegradable materials. In this research, nonwoven bamboo will be used as the top layer, nonwoven cotton will be used as the second layer, the absorbent core is to be made by the combination of kenaf and chitosan fibers as the third layer, cotton as the fourth layer, and cornstarch-based bioplastic sheets as the bottom layer. These biodegradable natural materials will change the menstrual process into a healthy one as well as create a robust ecological community.
文摘为改善聚乳酸的阻燃性能,利用植酸改性壳聚糖(PAMC)与三聚氰胺磷酸盐(MPP)复配得到一种新型膨胀型阻燃剂(IFR)体系,并将有机蒙脱土(OMMT)作为协效剂,通过熔融共混法制备阻燃聚乳酸(PLA)复合材料(PLA/PAMC/MPP/OMMT)。通过极限氧指数(LOI)、锥形燃烧量热(CONE)测试、垂直燃烧法(UL-94)和热重分析(TGA)测试分析复合材料的阻燃性能、燃烧性能和热稳定性能。采用扫描电镜(SEM)和X-射线光电子能谱(XPS)对复合材料的炭渣进行分析,研究了OMMT与PAMC/MPP在PLA复合材料中的阻燃协效作用。结果表明:与纯PLA相比,添加质量分数为25%的PAMC/MPP后,PLA2的LOI值、UL-94等级和800℃时的残炭量分别由21、NR和0.61%增至27.5、V-1级和17.28%,HRR曲线的峰值(PHRR)和总热释放量(THR)值分别由533.5 k W/m^2和81.7 MJ/m^2下降至270.2 k W/m^2和63.7 MJ/m^2。当添加质量分数为0.5%的OMMT后,PLA3的LOI值和残炭量继续增加至30.0和18.58%,PHRR和THR值进一步下降至251.6 k W/m^2和60.6 MJ/m^2,UL-94等级达到V-0级,且熔融滴落现象消失。OMMT与PAMC/MPP之间存在较好的协同效应,可有效改善PLA复合材料的阻燃性能,本研究结果可为制备绿色阻燃PLA复合材料提供理论依据。
