聚丙烯基双波长荧光防伪纤维的耐高温性分析

对聚丙烯基紫外/红外双波长荧光防伪纤维进行高温处理,研究了处理温度及处理时间对双波长荧光纤维的表面形态、结晶性能、荧光性能和力学性能的影响。结果表明:经高温处理后,双波长荧光防伪纤维的表面形貌无显著变化;在120℃高温下对双波长荧光纤维处理≤48 h时,纤维的结晶度随处理时间的延长而逐渐增大;而当处理时间达到72 h时,纤维结晶度略有减小;随高温处理时间的延长或随处理温度的升高,双波长荧光纤维的荧光强度总体上呈现出不断下降之势;高温处理后荧光纤维力学性能有所下降,但会随着时间的延长而趋于稳定。     

聚乳酸纤维的染色性能研究

本文选用不同种类的分散染料,设定不同温度、时间、p H、浴比、助剂等工艺条件,研究了聚乳酸纤维的染色性能。通过对染后纤维的表面色深值、染色牢度及断裂强力等项目的测试,优选出适宜的染料种类及工艺条件。此外,就染料结构对聚乳酸纤维染色性能的影响,及其常压染色的可行性问题进行了探讨。     

聚乳酸纤维的耐酸碱性

针对织物在加工、后处理以及服用过程中经常会遇到化学试剂作用的问题,研究了聚乳酸纤维在不同pH值、温度、时间等条件下的耐酸碱性。利用强力仪、扫描电镜(SEM)等测试仪器,测试分析了经酸碱液处理的聚乳酸纤维。结果表明:在影响聚乳酸纤维耐酸碱性的温度、时间和pH值三个因素中,pH值和温度起主要作用;热碱液对聚乳酸纤维强度影响很大,高温长时间的强酸性条件对纤维的损伤也较大;100℃、pH值为11、处理90 min时,纤维已失去纤维功能。从化学原理上分析了酸碱对聚乳酸纤维性能的影响,并从理论上解释了聚乳酸经酸碱水解的机制。     

熔纺聚乳酸纤维的结构与性能研究

通过熔融纺丝法制备了生物可降解左旋聚乳酸(PLLA)纤维,对纤维进行了拉伸和热定型等后处理,用电子单纤维强力仪和X-射线衍射仪研究了PLLA纤维的力学性能和结晶性能,讨论了纺丝温度、拉伸倍数、定型时间和定型温度等对纤维力学性能的影响。结果表明,当纺丝温度为200℃时,纤维可纺性最好。当拉伸倍数为4倍,热定型温度为60℃,定型时间为30min时,PLLA纤维具有最佳的力学性能,其晶区具有α晶型结构。     

聚乳酸短纤维的热定形工艺研究

研究了热定形温度与时间对聚乳酸短纤维力学性能及卷曲性能的影响。研究结果表明:聚乳酸短纤维的热定形温度应不高于120℃;随着热定形时间的增加,聚乳酸短纤维的卷曲率、卷曲回复率都明显增大,而卷曲弹性率下降。     

聚乳酸/丽赛/竹纤维混纺织物深色染色工艺研究

在聚乳酸纤维混纺织物的二浴法染色中,以表观色深K/S值作为衡量染色效果的依据,研究了第一浴染色工艺曲线、温度、pH值、时间对织物染色性能的影响;以染料的上染率K/S值为依据,研究了第二浴活性染料染色工艺曲线、温度、时间对织物染色性能的影响。提出了较佳的聚乳酸混纺织物深色染色配方及工艺流程。     

聚乳酸/玄武岩纤维复合材料的制备及性能研究

利用混杂原理,先将玄武岩纤维与聚乳酸纤维混合制成针刺毡,再与聚乳酸树脂复合,以提高树脂基体对增强体结构的渗透和结合性能。采用正交试验法,以混杂针刺毡中聚乳酸纤维含量、复合层压压力、复合层压温度为影响因素,讨论了混杂复合层压工艺对复合材料力学性能的影响。结果表明,采用混杂复合工艺有利于复合材料力学性能的改善,且混杂纤维含量在一定范围内时,复合材料的力学性能会随着混杂纤维含量的增加而线性增强,同时复合层压压力的增加也有利于复合材料力学性能的改善;采用混杂复合工艺时,复合层压温度对复合材料力学性能的影响规律不同于传统层压复合时复合层压温度对复合材料力学性能的影响,复合层压温度过高不利于复合材料力学性能的提高。     

过氧乙酸漂白亚麻短纤维工艺及性能研究

本文分析了过氧乙酸漂白亚麻短纤维的特点,探讨了过氧乙酸浓度、p H值、温度、时间对漂白性能的影响。结果表明:过氧乙酸有效地分解了色素,漂白效果好,同时纤维损伤较小,综合性能提高,改善了可纺性。最佳工艺参数为:过氧乙酸浓度9 g/L、p H值7、温度70℃、时间60 min。     

人发角蛋白液整理氧化棉织物的工艺研究

研究人发角蛋白液改性高碘酸钠氧化棉织物的整理工艺,测试并分析人发角蛋白浓度、整理液p H、整理时间和整理温度对氧化棉织物力学性能和防紫外线性能的影响,并采用SEM和FT-IR分析表征了氧化棉织物经人发角蛋白液整理后的微观形貌和化学结构。结果表明,人发角蛋白整理能显著提高氧化棉织物的防紫外线性能,其力学性能也略有提高;整理后,人发角蛋白在纤维表面吸附成膜并与纤维发生共价交联反应。     

生物酶催化接枝处理PPTA纤维表面研究

采用生物酶催化接枝的方法处理PPTA纤维表面,运用正交实验方法探讨了最佳反应条件。对处理前后PPTA纤维进行了红外、X射线光电子能谱、扫描电镜、力学性能和拉曼表征。结果发现:改性后纤维表面出现了环氧官能团,表面碳元素物质分数明显降低,氧元素物质分数明显增加;改性后纤维表面粗糙度有了显著提高,纤维与环氧树脂间的界面剪切强度提高了34%,而纤维力学性能没有受到明显影响。其最佳反应条件为反应温度48℃、酶质量浓度0.01 mg/ml、单体质量分数5%、氧化剂质量浓度0.03 g/ml和p H值6.9。     

UV‐excitable fluorescent poly(lactic acid) fibers

The UV‐excitable fluorescent poly(lactic acid) (PLA) fibers were spun by the traditional melt spinning process, and the effects of the fluorescent powder content (w(FP)) and draw ratio (DR) on the structure and properties of the fluorescent PLA fibers were investigated, respectively. The results showed that the emission spectra of fluorescent PLA fibers were peaked at 530 nm after UV excitation, indicating the PLA fibers would emit green light under UV light. With the increasing of w(FP), the relative fluorescence intensity of PLA fibers increased gradually, whereas more and larger protrusions were formed on the fiber surface due to the agglomeration of fluorescent powder, both the crystallinity and mechanical properties of fluorescent PLA fiber showed the decreasing trend with the increase of w(FP). With the increase of DR, the tensile strength of fluorescent PLA fibers increased gradually, whereas the relative fluorescence intensity of PLA fibers increased firstly and then decreased, and the highest fluorescence intensity was obtained when the DR was 3.6. In addition, the confocal laser scanning microscope can be used well to simulate the 3D distribution of fluorescent powder among the PLA fibers. POLYM. ENG. SCI., 56:373–379, 2016. © 2016 Society of Plastics Engineers     

表面处理对可生物降解黄麻/PLA复合材料结构和性能的影响

采用注塑成型法制备了生物降解黄麻短纤维增强PLA复合材料,通过力学性能测试及SEM,探讨了碱处理、碱和硅烷偶联剂KH550同时处理对复合材料结构和性能的影响。结果表明:两种处理方法均能够增加黄麻纤维的表面粗糙度,但碱和偶联剂KH550同时处理的效果要优于碱处理,且KH550改善了黄麻短纤维与PLA树脂之间的界面黏结性能提,高了黄麻/PLA复合材料的拉伸强度和弯曲强度。     

Biodegradable composites of poly(butylene succinate‐co‐butylene adipate) reinforced by poly(lactic acid) fibers

Biodegradable composites of poly(butylene succinate‐co‐butylene adipate) (PBSA) reinforced by poly(lactic acid) (PLA) fibers were developed by hot compression and characterized by Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical analyzer, and tensile testing. The results show that PBSA and PLA are immiscible, but their interface can be improved by processing conditions. In particular, their interface and the resulting mechanical properties strongly depend on processing temperature. When the temperature is below 120 °C, the bound between PBSA and PLA fiber is weak, which results in lower tensile modulus and strength. When the processing temperature is higher (greater than 160 °C), the relaxation of polymer chain destroyed the molecular orientation microstructure of the PLA fiber, which results in weakening mechanical properties of the fiber then weakening reinforcement function. Both tensile modulus and strength of the composites increased significantly, in particular for the materials reinforced by long fiber. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43530.     

挤出-注塑制备黄麻增强PLA复合材料及其性能

通过挤出共混、造粒、注射成型的方式制备了黄麻纤维填充聚乳酸(PLA)复合材料,研究了复合材料的力学性能以及黄麻与PLA之间的微观界面形貌。结果表明:黄麻的加入,并没有很好地改善黄麻/PLA复合材料的拉伸强度和弯曲强度;碱处理后的黄麻与PLA之间的界面性能有所改善;碱处理黄麻的加入,改善了黄麻/PLA复合材料的断裂伸长率与冲击韧性。     

Effects of alkali and alkali/silane treatments of corn fibers on mechanical and thermal properties of its composites with polylactic acid

Different chemically modified (including treatments with alkali alone and a combination of alkali and silane coupling agent) corn fibers (CFs) have been used as reinforcements in polylactic acid (PLA) matrix to improve the mechanical and thermal properties of the CF/PLA composites. A comparative study has been made to find out how the two treatments affect the mechanical and thermal properties such as tensile, flexural, and impact strengths and glass transition temperature (T_g), crystallinity, and heat deflection temperature (HDT) of the CF/PLA composites. Scanning electron microscopy analyses have been conducted to evaluate the fiber–matrix adhesion. It has been observed that the treatment with a combination of alkali and silane is more efficient in strengthening fiber–matrix bonding, and thus more significantly improving the tensile and flexural strengths, crystallinity, T_g, and HDT of the CF/PLA composites than the treatment with alkali alone. However, alkali treatment produces the optimal impact strength. Mechanisms have been proposed to interpret the observed changes in mechanical and thermal properties as a result of fiber treatments. It is inferred that the surface treatment of CFs with a combination of alkali and silane may also be applied in other CF–polymer composite systems. POLYM. COMPOS., 37:3499–3507, 2016. © 2015 Society of Plastics Engineers     

Nonwoven polylactic acid and flax biocomposites

Flax fiber‐reinforced polylactic acid (PLA) biocomposites were made using a new technique incorporating an air‐laying nonwoven process. Flax and PLA fibers were blended and converted to fiber webs in the air‐laying process. Composite prepregs were then made from the fiber webs. The prepregs were finally converted to composites by compression molding. The relationship between the main process variables and the properties of the biocomposite was investigated. It was found that with increasing flax content, the mechanical properties increased. The maximum tensile strength of 80.3 MPa, flexural strength of 138.5 MPa, tensile modulus of 9.9 GPa and flexural modulus of 7.9 GPa were achieved. As the molding temperature and molding time increased, the mechanical properties decreased. The thermal and morphological properties of the biocomposites were also studied. The appropriate processing parameters for the biocomposites were established for different fiber contents. POLYM. COMPOS., 34:1611–1619, 2013. © 2013 Society of Plastics Engineers     

On the effectiveness of the addition of milkweed floss fibers on processing and mechanical properties of PLA biocomposites

This study aimed at investigating the reinforcement effect of milkweed (MW) floss, a smooth and homogeneous natural fiber with a wide hollow lumen, on bio-based polymer composites. First, MW floss was thoroughly characterized in terms of morphology, surface roughness, and tensile and thermal resistance. Then, MW floss was compared to flax fibers, one of the most widely used natural fibers in the composite industry. Subsequently, bio-based composites made of polylactic acid (PLA) and 1 wt% MW floss were produced by injection molding and compared to composites reinforced with 1 wt% of flax fibers. Finally, thermal behavior, mechanical properties, and impact resistance of composites were determined. Results showed that MW floss, with respect to flax fibers, exhibits lower tensile modulus, ultimate tensile strength, surface roughness as well as a shorter critical length. Nonetheless, and despite the lower intrinsic properties of MW floss, UTS and impact resistance of MW/PLA composites were found to be 60% and 15% higher than those of Flax/PLA composites, respectively. In addition, micrographs of MW/PLA interface revealed a lack of adhesion in MW/PLA, which should be overcome by surface treatment in upcoming work.     

聚甲醛纤维制备工艺及其性能的研究

以聚甲醛(POM)切片为原料,在200～210℃进行熔融纺丝制得POM长丝。利用DSC、Olympus偏光显微镜、单纱电子强力仪测定了POM纤维结晶度、熔点、取向度和纤维的机械性能;研究了后处理对POM纤维性能的影响以及拉伸对POM纤维耐酸碱性能的影响。结果表明:(1)POM纤维耐碱性良好,拉伸可以提高POM纤维结晶度、取向度、断裂强度以及耐酸性,但是使断裂伸长率减小;最佳拉伸温度在110℃左右,拉伸倍率在6～8之间。(2)热定形温度对POM纤维结晶度和熔点影响不大,延长热定形时间使POM结晶度、熔点降低;最佳热定形条件为在140℃下热定形4min。(3)经过拉伸热定形后的POM纤维的最大断裂强度和断裂伸长率分别为7.41cN/dtex和19.2%。