Improving the Compatibility of Biodegradable Poly (Lactic Acid) Toughening with Thermoplastic Polyurethane (TPU) and Compatibilized Meltblown Nonwoven

Poly (Lactic Acid) (PLA) is a biodegradable polymer which originates from natural resources such as corn and starch, offering excellent strength, biodegradability, nevertheless its inherent brittleness and low impact resistance properties have limited its application. On the other hand, Thermoplastic Polyurethane (TPU) has high toughness, durability and flexibility, which is one of the most potential alternatives for enhancing the flexibility and mechanical strength of Poly (Lactic Acid) (PLA) by blending it with a compatibilizer. With the aim to improve the mechanical and thermal properties of Poly (Lactic Acid) (PLA) meltblown nonwovens, The Thermoplastic Polyurethane (TPU) was melt blended with Poly (Lactic Acid) (PLA) at the different corresponding proportions for toughening the Poly (Lactic Acid) and the corresponding PLA/TPU MBs (meltblown nonwovens) were also manufactured. Joncryl ADR 4400 is mixed into the PLA matrix during processing. It was found that Joncryl had a much higher chain extension that substantially increased the molecular weight of the PLA matrix. SEM study revealed that Joncryl ADR 4400 is a good compatibilizer. Moreover, in this study, the crystallization, thermal and rheological behaviors of the corresponding PLA and TPU blends were also investigated. PLA/TPU MBs were also characterized by morphology and mechanical properties. The rheological property of the PLA/TPU meltblown nonwoven revealed that the viscosity is increasing as the amount of TPU is increasing in the blend, PLA/TPU meltblown nonwovens exhibited excellent mechanical properties;they are soft, elastic, and have certain tensile strength. New materials have potential applications in the medical and agricultural fields. Joncryl ADR 4400 compatibilized blends showed higher strength than simple PLA/TPU blends at the same PLA/TPU ratio.

氧化石墨烯的表面改性及对尼龙6纤维的力学增强作用

为了提高尼龙6(PA6)纤维的力学性能,利用十二烷基胺(DA)对氧化石墨烯(GO)表面改性得到氨基化的氧化石墨烯(A-GO),将A-GO与PA6熔融共混纺丝制得A-GO/PA6复合纤维。通过对A-GO及A-GO/PA6复合纤维的结构表征,结果表明DA成功接枝于GO,相较于未改性的GO,A-GO的层间距增大了0.37nm,改性的A-GO与基体PA6具有良好的界面相互作用,可以实现较为均匀的分散;A-GO在PA6纤维中起异相成核作用,促进了尼龙6纤维的结晶,并诱导PA6由α晶型向γ晶型转变;A-GO/PA6复合纤维较纯PA6纤维的5%热失重温度提高了6.1~8.9℃,表现出更高的热稳定性;当A-GO的含量仅为0.1%时,复合纤维的拉伸强度是纯PA6纤维的1.4倍。

银/还原氧化石墨烯负载聚丙烯熔喷非织造材料的制备及抗菌抗静电性能

为了赋予聚丙烯(PP)熔喷非织造材料良好的抗菌和抗静电性能,使其在医疗卫生等领域得到更广泛的应用,首先利用聚多巴胺(PDA)和聚乙烯亚胺(PEI)对PP熔喷非织造材料进行表面改性得到P-PP,再通过微波辅助法负载银/还原氧化石墨烯(Ag/rGO)得到了Ag/rGO-P-PP复合熔喷非织造材料。同时制备了单独负载rGO、Ag的rGO-P-PP、AgP-PP和未经表面改性处理的Ag/rGO-PP材料。通过对复合材料的结构和性能表征,表明Ag/rGO成功负载到P-PP熔喷非织造材料的表面,得到的复合材料对大肠杆菌和金黄色葡萄球菌的抑菌率均大于99.99%,表面电阻率达到1.77kΩ,半衰期达到0.01 s。与rGO-P-PP、Ag-P-PP和Ag/rGO-PP相比,Ag/rGO-P-PP减少了纳米Ag的团聚,负载较均匀,抗菌和抗静电效果也最佳。

聚乳酸熔喷法非织造材料的应用及改性研究进展

为促进聚乳酸熔喷法非织造材料在医疗卫生、过滤分离和环境保护等领域的功能性应用,进而缓解传统石油基熔喷法非织造材料所带来的资源短缺与环境污染问题,文中对聚乳酸熔喷法非织造材料的成型、应用及改性研究进行了梳理,分析了聚乳酸熔喷法非织造材料的改性方法,并总结了聚乳酸熔喷法非织造材料的增韧改性、增塑改性、耐热改性及其他功能性改性。最后指出增强聚乳酸熔喷法非织造材料的功能性是其应用推广的必要前提,通过对聚乳酸熔喷法非织造材料的改性研究分析,为后续聚乳酸熔喷法非织造材料的研究与发展提供理论支持。

Ultrastable MOF-based foams for versatile applications

Metal-organic frameworks(MOFs)are attractive for promising applications but plagued by difficult recovery and deployment due to their intrinsic nano/micro powder nature.Although significant efforts have been made to develop separable solid matrixes for MOF supporting,the poor loading stability and durability of MOFs still challenge their engineering applications.Here,we present a facile and effective approach to fabricate MOF-based melamine foams(MFs)(denoted as MOFiths)with ultrahigh loading stability and operation stability,easy separation,and high-efficient performance for versatile robust applications.By adopting our approach,numbers of typical fragile MOFs characterized with wide ranges of particle size(from~nm to~μm)can be precisely incorporated into MFs with controllable loading ratios(up to~1,600%).Particularly,the produced MOFiths show excellent capacities for the highly effective and durable water purifications and acetalization reactions.100%of organic pollutants can be rapidly destructed within 10 min by MOFiths initiated Fenton or catalytic ozonation processes under five successive cycles while the maximum adsorption capacity of MOFiths toward Pb(II),Cd(II),and Cu(II)reaches to 422,222,and 105 mg·g^(-1),respectively.This study provides a critical solution to substantially facilitate the engineering applications of MOFs for long-term use in practice.