The influences of the coagulation bath concentration in N-Methyl-Morpholine-N-oxide(NMMO)processon the maximum spinning speed and the mechanicalproperties(the modulus,the tenacity and the extensionat break)of Lyocell ...The influences of the coagulation bath concentration in N-Methyl-Morpholine-N-oxide(NMMO)processon the maximum spinning speed and the mechanicalproperties(the modulus,the tenacity and the extensionat break)of Lyocell flbers are investigated.The resultsshow that the maximum spinning speeds decrease withthe increasing coagulation bath concentration.When theconcentration of coagulation bath is 10％(wt％),the te-nacity and modulus of the obtained Lyocell fibers reachmaximum and the extension at break of the fibers reach-es minimum.展开更多
Lyocell fibers are subject to fibrillate under wet conditions, which severely affects the appearance of this kind of fabrics. Cross-Unking treatment is an important way to prevent fibrillation of lyocell fibers. In th...Lyocell fibers are subject to fibrillate under wet conditions, which severely affects the appearance of this kind of fabrics. Cross-Unking treatment is an important way to prevent fibrillation of lyocell fibers. In this study, two kinds of traditional N-hydroxymethyl cross-linking agents were used to treat lyocell fibers and the wet abrasion values of lyocell fibers were measured in a wet abrasion test. The results show the wet abrasion values of lyocell fibers increase with the increasing concentration of the cross-linking agents, which indicates the anti-fibrillation property of the treated fibers has been improved. But the mechanical properties of the treated fibers decreased in some extent. The FT-IR spectroscopy analysis shows that the lyocell fibers have cross-linked with cross-linking agents. The SEM analysis results show the fibers treated by 4% DMDHEU or 5% SECO have good anti-fibrillation properties.展开更多
The carding of the Lyocell cellulose fiber was done with a cylindrical cross lap machine supplied by Cormatex Prato, Italy. Several mats were made by carding and needle punching in order to have a compact and well ent...The carding of the Lyocell cellulose fiber was done with a cylindrical cross lap machine supplied by Cormatex Prato, Italy. Several mats were made by carding and needle punching in order to have a compact and well entangled mat suitable for reinforcement. The speed of the cross lap machine, the frequency of needle punching, the number of times the mat goes through needle punching, the feeding rate of the carded fiber and the depth of needle penetration determined the level of entanglement of the Lyocell fiber which ultimately increased the mechanical properties of the fiber. The good mechanical properties of the carded Lyocell fiber made it a renewable and environmentally friendly alternative as reinforcement in composite manufacturing. Compared with other jute fiber reinforced composites, the mechanical properties of the resulting Lyocell composites were found to be better. Regenerated cellulose fiber (Lyocell) composites were environmentally friendly and the mechanical properties were comparable to those of natural fibers.展开更多
As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Ly...As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Lyocell fiber is claimed as“green and eco-friendly fiber”with a good application prospect in the 21st century.The preparation of lyocell fiber is based on the cellu-losic non-derivative solution system,i.e.,N-methylmorpholine-N-oxide system which is nontoxic and recyclable.In this review,firstly,the demands of dissolving pulp properties for regenerated-cellulosic fiber(RCF),especially for lyocell fiber,were introduced in detail.Next,the whole manu-facturing processes including pretreatment,preparation of spinning dope,spinning,posttreatment and efficient solvent recovery technologies were reviewed emphatically.Then,the properties and structural characteristics of lyocell fiber were illustrated.At last,some suggestions were proposed for lyocell fiber development in China.展开更多
Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morph...Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morphology observation, MTT and DNA assay were used to evaluate the influence of the composite on the morphology, growth and proliferation of cultured L-929 cells. Results: The composite did not impair the morphology of cultured cells in vitro. MTT and DNA assay demonstrated that the growth and proliferation of the cultured cells were not significantly inhibited by the composite. Conclusion : The composites have fine cytocompatibility and are safe for clinical use of reconstruction of chest wall defects.展开更多
基金National Natural Science Foundation of China.(Ref: No.29874029)
文摘The influences of the coagulation bath concentration in N-Methyl-Morpholine-N-oxide(NMMO)processon the maximum spinning speed and the mechanicalproperties(the modulus,the tenacity and the extensionat break)of Lyocell flbers are investigated.The resultsshow that the maximum spinning speeds decrease withthe increasing coagulation bath concentration.When theconcentration of coagulation bath is 10％(wt％),the te-nacity and modulus of the obtained Lyocell fibers reachmaximum and the extension at break of the fibers reach-es minimum.
文摘Lyocell fibers are subject to fibrillate under wet conditions, which severely affects the appearance of this kind of fabrics. Cross-Unking treatment is an important way to prevent fibrillation of lyocell fibers. In this study, two kinds of traditional N-hydroxymethyl cross-linking agents were used to treat lyocell fibers and the wet abrasion values of lyocell fibers were measured in a wet abrasion test. The results show the wet abrasion values of lyocell fibers increase with the increasing concentration of the cross-linking agents, which indicates the anti-fibrillation property of the treated fibers has been improved. But the mechanical properties of the treated fibers decreased in some extent. The FT-IR spectroscopy analysis shows that the lyocell fibers have cross-linked with cross-linking agents. The SEM analysis results show the fibers treated by 4% DMDHEU or 5% SECO have good anti-fibrillation properties.
文摘The carding of the Lyocell cellulose fiber was done with a cylindrical cross lap machine supplied by Cormatex Prato, Italy. Several mats were made by carding and needle punching in order to have a compact and well entangled mat suitable for reinforcement. The speed of the cross lap machine, the frequency of needle punching, the number of times the mat goes through needle punching, the feeding rate of the carded fiber and the depth of needle penetration determined the level of entanglement of the Lyocell fiber which ultimately increased the mechanical properties of the fiber. The good mechanical properties of the carded Lyocell fiber made it a renewable and environmentally friendly alternative as reinforcement in composite manufacturing. Compared with other jute fiber reinforced composites, the mechanical properties of the resulting Lyocell composites were found to be better. Regenerated cellulose fiber (Lyocell) composites were environmentally friendly and the mechanical properties were comparable to those of natural fibers.
基金This work was financially supported by National Key Research and Development Program of China(No.2017YFB0308200 and No.2017YFE0101500).
文摘As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Lyocell fiber is claimed as“green and eco-friendly fiber”with a good application prospect in the 21st century.The preparation of lyocell fiber is based on the cellu-losic non-derivative solution system,i.e.,N-methylmorpholine-N-oxide system which is nontoxic and recyclable.In this review,firstly,the demands of dissolving pulp properties for regenerated-cellulosic fiber(RCF),especially for lyocell fiber,were introduced in detail.Next,the whole manu-facturing processes including pretreatment,preparation of spinning dope,spinning,posttreatment and efficient solvent recovery technologies were reviewed emphatically.Then,the properties and structural characteristics of lyocell fiber were illustrated.At last,some suggestions were proposed for lyocell fiber development in China.
基金Supported by the Sci & Tech Development Foundation of Shang-hai (No. 024419076)
文摘Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morphology observation, MTT and DNA assay were used to evaluate the influence of the composite on the morphology, growth and proliferation of cultured L-929 cells. Results: The composite did not impair the morphology of cultured cells in vitro. MTT and DNA assay demonstrated that the growth and proliferation of the cultured cells were not significantly inhibited by the composite. Conclusion : The composites have fine cytocompatibility and are safe for clinical use of reconstruction of chest wall defects.
