蒙脱土改性PET纤维性能

采用熔融插层法制备聚对苯二甲酸乙二酯（PET）/蒙脱土（MMT）纳米复合材料,对其纤维的结晶性能、力学性能及染色性能进行详细研究.结果表明,与纯PET纤维相比,蒙脱土改性PET纤维具有较高的模量和较低的收缩率,改性纤维的上染率亦有明显提高.含磺酸基团改性的聚对苯二甲酸乙二酯（CDP）/MMT纤维的上染率和上染速率大于PET/MMT纤维,表明蒙脱土和聚合物中的离子基团对促进PET纤维的染色性能有协同作用.     

无声放电对聚酯织物表面的等离子体接枝改性

利用无声放电方法对聚酯（ＰＥＴ）纤维表面进行接枝改性,为改善聚酯织物的染色性能提供了一条新途径,傅里叶红外光谱（ＦＴＩＲ）和Ｘ射线光电子能谱（ＸＰＳ）表明,ＰＥＴ纤维经无声放电引发气相接枝丙烯酸改性后,表面的羰基、羟基和羧基等极性基团增加,氧碳摩尔分数比增大。扫描电镜（ＳＥＭ）观察发现纤维表面粗糙度随放电时间增加而增大,改性后的涤纶对碱性染料的上染率有所提高。     

Non-isothermal Crystallization Kinetics of Modified Poly(ethylene terephthalate) with Ultraviolet Protection

The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer wider non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system.     

Influence of Thermal Treatment on the Structure and Thermal Properties of Kaolin Modified Polyester Fibers

Modified polyester fibers were obtained using 2% and 6% of kaolin blends through melt spinning.The influences of two thermal treatments maintaining the original tension(180 ℃×2 min and 200 ℃×1 min)on the structure and properties of fiber were compared.The changes of grain size and crystallinity of fiber were investigated by X-ray diffraction(XRD).The changes of thermal properties of fibers were analyzed using dynamic mechanical analyzer(DMA).The results show that the crystalline structure of kaolin modified polyester fiber doesn't change with the thermal treatment.With the kaolin content increasing,the grain size of fiber changed.The higher the thermal treatment temperature is,the higher the crystallinity of fiber is.There are two glass-transition temperatures for kaolin modified:the lower one is the glass-transition temperature of polyester fiber matrix,and the higher one is derived from the heterogeneous blend of polyester matrix and nano kaolin.The higher the kaolin content is,the higher the glass-transition temperature is.Thermal treatment could increase the compatibility of polyester matrix and nano kaolin.There was only one glass-transition temperature for the thermal treatment fiber,and the heat resistance of fiber was improved.Thermogravimetric analysis-differential scanning calorimetry(TGA-DSC)results of kaolin modified polyethylene terephthalate(PET)matrix indicate that the decomposition temperature of PET fibers,kaolin modified PET fibers,and thermal treated fibers were little different within 40%-60% of weight loss rate range.     

紫外辐照表面接枝纤维的表征

本文通过电子能谱法,全反射红外光谱法、纤维染色性能和吸湿性能的测定,纤维与环氧树脂粘结后拔出力的测试等表征了经紫外辐照表面接枝的高强高模聚乙烯纤维和高强聚酯纤维的表面接枝程度,这些实验结果同时也肯定了紫外辐照接枝纤维的表面性能得到了很好的改善。     

Structural basis of ultraviolet-B perception by UVR8

The Arabidopsis thaliana protein UVR8 is a photoreceptor for ultraviolet-B. Upon ultraviolet-B irradiation, UVR8 undergoes an immediate switch from homodimer to monomer, which triggers a signalling pathway for ultraviolet protection. The mechanism by which UVR8 senses ultraviolet-B remains largely unknown. Here we report the crystal structure of UVR8 at 1.8?? resolution, revealing a symmetric homodimer of seven-bladed β-propeller that is devoid of any external cofactor as the chromophore. Arginine residues that stabilize the homodimeric interface, principally Arg?286 and Arg?338, make elaborate intramolecular cation-π interactions with surrounding tryptophan amino acids. Two of these tryptophans, Trp?285 and Trp?233, collectively serve as the ultraviolet-B chromophore. Our structural and biochemical analyses identify the molecular mechanism for UVR8-mediated ultraviolet-B perception, in which ultraviolet-B radiation results in destabilization of the intramolecular cation-π interactions, causing disruption of the critical intermolecular hydrogen bonds mediated by Arg?286 and Arg?338 and subsequent dissociation of the UVR8 homodimer.     

Effects of solar ultraviolet radiation on the photochemical efficiency, photosynthetic pigments and biomass production of Spirulina platensis

Effects of solar ultraviolet radiation (UVR) on Spirulina platensis were studied by investigating its photochemical efficiency, photosynthetic pigments and biomass production while exposed to full spectrum solar radiation or depleted of UVR for understanding how and to what extent UVR influences its photosynthe tic physiology and production. It was found that UVR brought about an extra inhibition of photochemical efficiency by 26%—30%. The greatest inhibition of pho tochemical efficiency in S. platensis was observed at noontime, and then recovered to some extent in late afternoon no matter which treatment they were exposed to. The contents of chlorophyll a, phycocyanin and carotenoids increased during initial stage of the exposure, but decreased with elongated exposure. UVR decre ased the biomass yield by about 6%. It indicated that filtering out UVR of solar radiation would raise the productivity of S. platensis, which is an important factor that should be considered in the production.     

紫外辐射时空变化规律研究进展

紫外辐射(ultraviolet radiation, UVR)会对人体健康,陆生及水生有机体产生伤害作用。因此,了解紫外辐射在全球及中国的分布及变化状况十分重要。综述了UVR在全球和中国地表分布状况,及影响因素。从全球而言,赤道附近南北纬23°之间UVR最强,亚马孙热带雨林地区低于周边地区,一些高海拔地区也是UVR高值区。中国UVR分布从南向北逐渐减小,从东向西增加,青藏高原一直是高值区;从时间分布来看,北半球和中国紫外辐射强度基本一致,1—7月紫外线逐渐增强,7月达到最大值,后逐渐减弱,12月达最小值。南半球时间变化与之相反,最高值出现在1月份。且因人类活动排放的消耗臭氧层物质作用,臭氧层仍持续减少,因此到达地表UVR强度最大将增加。从影响地表UVR分布因素而言,天文因素、臭氧、云、气溶胶及大气污染物、海拔高度、地表反照率等因素均对地表UVR产生重要影响。因此,加强UVR监测与预报,以及加强UVR对陆生与水生生态系统研究对生产、生活及科学研究等领域均十分重要。     

PLA纤维的性能研究

本文研究了PLA纤维的表面形态、物理机械性能、吸水性、在碱性洗涤剂中的收缩性,以及酸、碱和有机溶剂对PLA纤维的强力损伤程度.结果表明:PLA纤维的强度与形态和PET纤维相近,吸水率比棉小但比PET纤维大,PLA纤维在碱性条件下缩水率和强力损失速率大,PLA纤维抵抗酸碱和有机溶剂的能力大小为:丙酮＞盐酸＞碳酸钠＞氢氧化钠.     

Studies on the Structures and Properties of Latent - crimp Copolyestcr Fibers

The internal causes of latent-crimp were analyzed bystudying the supermolecular structures of the standardpolyester fibers(PET),copolyester fibers(IPET)andtheir side-by-side composite fibers(PET/IPET)inthis paper.It is concluded that IPET and PET/IPEThave better latent-crimp ability because of their asym-metric supermolecular structures.At the same time,they have good dyeability and mechanical properties.Soit is a simple and low cost process to manufacture latent-crimp continuous fibers by melt-spinning of the co-polyester IPET.     

Combustion forming hollow nanospheres as a ceramic fortress for flame-retardant fiber

Simple, effective and safe flame retardants are required to improve flame retardant properties of polymer fibers.However, traditional additive flame retardants, such as halogen-flame retardants and intumescent flame retardants, are likely to cause phase separation of functional phases due to their poor dispersibility and compatibility, or are difficult to be suitable for the high temperature processing conditions of melt-spun fibers. Here, in an effort to develop a practical flame retardant system in which zinc diphosphinate(DEPZn) and D-glucose(DG)were selectively incorporated into polyethylene terephthalate(PET) fiber was developed. As a result, the dense nano-scale zinc phosphate microspheres were formed on the surface and inside the residual carbon during combustion. Thus, PET fibers were endowed with excellent flame retardancy through a thermal barrier and enhancement of physical strength for the carbon layer. Moreover, a synergistic flame-retardant effect was found between DEPZn and DG. DG reduced the size of the zinc phosphate nanosphere from 200 nm to 50 nm, making the carbon layer denser and smoother. As a result, the peak heat release of the resultant PET composite fiber decreased to 410 k W/m~2 compared 1276 k W/m~2 for neat PET fiber. Moreover, the total smoke release also dropped from 71 MJ/kg of neat PET fiber to 64 MJ/kg for PET composite fibers. These results provide a promising strategy for the production of industrialized PET flame retardant fibers.     

稀土MOF改性棉织物的制备及荧光性能

基于水溶液的层层自组装方法,在棉织物表面以不同芳香酸和稀土阳离子为原料制备稀土金属有机骨(rare earth metal-organic framework,REMOF)材料,得到一系列REMOF改性棉织物。采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、荧光光谱分析(PL)以及紫外吸收光谱(UV-vis)对REMOF改性棉织物进行表征分析。荧光强度对比结果表明,当以1,4对苯二甲酸或1,3,5均苯三甲酸为配体时,在324 nm波长激发下改性棉织物于617 nm处出现Eu 3+的特征红色荧光。所有改性棉织物的UPF(ultraviolet protection factor)值均为50^+,T(UV-A)和T(UV-B)值均小于5%,表明改性棉织物具有优良的抗紫外性能。     

海岛纤维结构形态与染色性能的研究

通过色差仪、DSC、结晶速度测量、显微图像分析以及动态机械热分析研究了四种海岛纤维的结晶度、结晶速度、晶粒大小、玻璃化温度与染色性能的关系.结果表明:结晶度小,结晶速度慢,晶粒尺寸大,玻璃化温度低等等均有利于纤维染色性能的提高.     

Surface Graft Polymerization of PET and PE Fibers by UV Irradiation and Their Characteristics

Polyethylene terephthalate(PET)and polyethylene(PE)fibers were surface photo-grafted with acrylic acid(AA)by using UV irradiation photochemical initiationduring a continuous winding process within 1-2 min-utes.The grafted fibers were characterized by measure-ments of dye uptaking,moisture regain,pull-out forcesof monofilament from cured matrix,as well as by analy-sis of ESCA and ATR-FTIR spectra.All these resultsconfirm that the surface behavior of the UV-irradiationgrafted fibers was greatly improved.It was also provedthat the original excellent mechanical properties of the fi-bers were well-retained after the surface grafting treat-ment.     

确定PTT/PET并列复合纤维卷曲结构的材料参数

通过实测3种不同横截面形状的PTT(聚对苯二甲酸丙二醇酯)/PET(聚对苯二甲酸乙二醇酯)自卷曲纤维的拉伸曲线和两组分在横截面中的面积分布,得到PTT和PET两组分材料的弹性模量比为0.333.由Denton的曲率计算模型推导得到3种特殊截面的自卷曲纤维的曲率表达式,结合实测的卷曲曲率,求得PTT和PET两组分的热收缩率差是在7%～10%之间.最后,用数值模拟方法考查了这3种横截面的自卷曲纤维的卷曲曲率随着两组分收缩率差、弹性模量比的变化关系,得到不同横截面形状及材料参数对PTT/PET自卷曲纤维卷曲曲率的影响.     

原位复合材料MPPOG／LCP体系加工与性能研究

本文以一种含柔性链的共聚酯液晶高聚物（ＰＥＴ／ＰＨＢ６０）和玻璃纤维增强的改性聚苯醚（ＭＰＰＯＧ）的共混物为对象，叙述了在单螺杆挤出机和单螺杆注塑机上形成原位复合材料时不同液晶含量下的共混物的微观结构和性能，结果表明ＬＣＰ的加入降低了ＭＰＰＯＧ的粘度，改善了加工性能，但共混物的机械性能改善不明显。ＭＰＰＯＧ与ＬＣＰ是不相容的，它们的纤维尺寸及织构也存在差别。     

Hydrolysis-resistant Polyethylene Terephthalate （PET） Fiber

For certain industrial applications, the mechanical properties of PET fiber can be deteriorated from hydrolysis because the terminal carboxylic groups promote the degradation of macromolecules under high moisture and high temperature. It limits the wide applications of PET fiber in some special cases. In this paper, three additives are selected to improve the hydrolytic stability through the reaction of bi-functional groups on additive molecules with carboxyl groups on PET molecules. The additives can serve not only as hydrolysis stabilizers, but also as agents to increase the molecular weight and consequently to improve PET fiber mechanical properties. PET pellets were blended with additive before spinning, and melt spun into fiber. The fibers were then hydrolyzed in an autoclave by saturated vapor at 140℃ for a period of time. Measurements of intrinsic viscosity, terminal carboxylic group value and strength of polyester fibers were carried out to study the effects of hydrolysis resistance. Results show that 2, 2＇-bis （2-oxazoline） has best hydrolysis-resistibility and the chainextension effect at the same time.     

常压阳离子染料易染共聚酯纤维微观结构与性能

采用红外光谱分析和X射线衍射法,表征常压阳离子染料易染共聚酯(ECDP)纤维的微观结构,并通过测试ECDP纤维和聚酯(PET)纤维的拉伸性能、吸湿性能和导电性能,探讨了微观结构对纤维性能的影响.结果表明:ECDP纤维中第三组分间苯二甲酸5磺酸钠的加入使结晶度减小,因此,断裂强度和初始模量比PET纤维小,而断裂伸长率有所增加,回潮率较大,体积比电阻较小.     

Structural Changes of Polyethylene Terephthalate Fibers Grafted by Acrylamide

A group of grafted PET fibers with different graft yield are formed by grafting acrylamide onto the PET main chains. The structure of grafted fibers are studied by scanning electronic microscope ( SEM ), infra-red spectrophotometer ( IR ), and differential scanning calorimetry(DSC). At the same time, the moisture regain, dyeability, strength, and elongation at break of the samples are measured and their relations with structural changes are discussed. Compared with ungrafted fiber, shape of the fiber cross-section, IR characteristic absorption peaks, and melting behavior of the grafted fibers have been changed, causing the fiber dyeability and moisture regain to be increased, and mechanical properties to be changed.     

Effects of Process Technology on Structure and Properties of HMLS Fibers

High modulus low shrinkage (HMLS) fibers have been prepared by using higher viscosity PET chips. The effects of the process conditions on their structure and properties have been studied by various testing techniques. The results show that the suitable spuming speed for preparing of HMLS fibers is 2 000 - 2 800 m/ min. With the increase of the spinning speed, the density, crystallinity, and birefringence of the initial fibers increase obviously, but the shrinkage ratio decreases rapidly. The effects of process technology on properties of the HMLS fibers have also been discussed.