【作者】 叶敏；

【导师】 王依民；

【作者基本信息】 东华大学 ， 材料加工工程， 2011， 硕士

【摘要】 近几年,中国发制品进入快速发展时期,合成纤维制得发制品不受资源制约,且容易根据市场需求变换花色品种,附加值高,已成为发制品发展的主流。从全球来看,目前发制品主要用于装饰、特种工作需求(律师、演员)、教学(美容美发行业)和弥补生理缺陷等。发制品更多地视为“头上时装”用于“扮靓”。随着人们生活水平的不断提高,自然舒适及功能型的发制品更加受到青睐。保温凉爽型发制品纤维的研制对不同季节穿戴假发的消费者来说将是一种福音。本课题采用的相变材料为十八烷(C18H38),相变温度为25-32℃(相转变温度范围和人体温度变化范围相似)。由于低分子量的纯十八烷,其各方面力学性能较差,本课题的皮芯复合结构发制品纤维芯层为十八烷和EVA30/30的共混物。在十八烷中添加EVA30/30以提高其力学性能,除了有利于纤维加工成型外,EVA30/30和十八烷包覆体系的热性能、封装效果及持久稳定性都较好。相变材料十八烷与EVA30/30的网络状结构相互间有排挤现象,使EVA30/30的网络状结构被挤压后变得松散。因此十八烷的含量越多,EVA30/30的网络状结构被挤压松散得越严重：EVA30/30/十八烷共混体系在非等温过程中,晶粒的增长受阻,体系的结晶能力更加地降低；EVA30/30/十八烷共混膜的断裂强度和断裂伸长率都下降；EVA30/30/十八烷共混膜样片渗漏测试时渗漏现象越明显,当十八烷的含量≤55%时,质量损失率随着取样时间的增加而增加,但是变化相当缓慢,当十八烷含量≥60%时,质量损失率随着取样时间的增加而增加,变化非常明显。因此本课题皮芯复合结构发制品纤维的芯层选取十八烷的含量为55%的EVA30/30/十八烷共混物。由于芯层所含的相变材料十八烷为低温相变材料,熔点和分解点都较低,皮层材料的熔融纺丝温度也要较低才能与之匹配,以防止在纺丝过程中芯层所含的低温相变材料因温度过高而分解。本课题皮层采用EVA28/150/HDPE共混物,选择EVA28/150为皮层的主要原料是因为一、其纺丝温度够低；二、制得的纤维的皮层和芯层中分别含有大量的EVA28/150和EVA30/30,具有良好的相容性,在今后的使用中不易相互脱落。选择HDPE共混在皮层中主要是因为可以提高共混纤维的强度,同时又可以兼顾到EVA28/150的低熔点。实验发现,HDPE的含量为15%时,EVA28/150/HDPE共混物的可纺性好,共混纤维的力学性能最佳,因此本课题皮芯复合结构发制品纤维的皮层选取HDPE的百分含量为15%的EVA28/150/HDPE共混物。本课题采用双组份复合纺丝机熔融纺制备皮芯复合结构发制品纤维。红外光谱分析说明相变材料十八烷已填充进皮芯复合结构发制品纤维；牵伸温度为50℃左右,牵伸倍数分别为2.5,3,3.5,4倍。随着牵伸倍数的增加,复合纤维断裂强度上升,断裂伸长率下降,其断裂强度、断裂伸长率随着芯层含量的增加而下降。当定伸长率≤75%,定负荷<40cN,无论是一次拉伸还是反复5次拉伸,皮芯复合结构发制品纤维都具有良好的弹性回复率。随着芯层含量的增加即相当于十八烷含量的增加,纤维的弹性回复率降低；当皮芯结构完整时,在EVA30/30共混包覆十八烷比较理想的效果下有了皮层共混物的进一步包覆,整个皮芯复合结构纤维所含的相变材料可保持不渗漏的,达到理想状态；按相变材料含量=(│ΔH1│)/(│ΔH2│)计算所得的相变材料十八烷在皮芯复合结构发制品纤维中的实际含量基本符合理论值；皮芯复合结构发制品纤维经历50次冻融循环之后,相变特性变化较小,具有较好的冻融循环稳定性。本课题解决了常规发制品纤维不能在周围形成温度基本恒定的微气候,从而实现温度调节功能的问题,弥补了现有技术生产的传统假发不能智能调温的不足。更多还原

【Abstract】 In recent years, chinese hair products are going into an rapid development period. Synthetic wig fibers aren’t subject to resource limit,and change color, a great variety of design according to market, and own high added-value, and therefore become the mainstream of hair products. From a global point of view, hair products are mainly used for decoration, special need works(lawyers, actors or actresses), teaching (beauty salon industry), and compensation for defects. Hair products are more as "fashion of head" for "Dressing". With the continuous improvement of living standards, comfortable and functional hair products are favored much better. Development of wig fibers cool in summer and warm in winter would benefit consumers wearing wigs in different seasons.Phase change material octadecane (C18H38) is used in this study with phase transition temperature of 25-32℃(phase transition temperature range is similar to the temperature range of human body). Octadecane is a kind of low molecular weight and poor mechanical property materials, and the core of core-sheath bicomponent wig fibers are EVA30/30/octadecane blends. Therefore, EVA30/30 is added into octadecane to improve its mechanical property, processing behavior, thermal property, package effect and lasting stability. The EVA30/30 network-like structure becomes loose because of the clash of octadecane and network-like structure. It is found that the more the content of octadecane is, the looser the network-like structure of EVA30/30 becomes:during non-isothermal process, the grain growth in EVA30/3o/octadecane blends is blocked and the crystallization ability of the system further declines; the tensile strength and elongation at break of EVA3o/3o/octadecane blend membrane decline; leaking test of EVA3o/3o/octadecane blend membrane indicates that leakage is more obvious, when octadecane is <55wt%, the mass loss rate increases very slowly with the increase of sampling time. When octadecane is≥60wt%, however, the mass loss rate increases obviously with the increase of sampling time. Therefore, the appropriate amount of core for core-sheath bicomponent wig fibers are EVA30/30/octadecane blends with 55wt% octadecane. Octadecane in the core is low-temperature phase change material with low melting point and decomposition temperature, so the sheath materials must have a low melt spinning temperature to prevent phase change material from decomposing in the spinning process. The sheath are EVA28/150/HDPE blends with EVA28/150 as based raw materials, the reasons are listed as follows: first, the spinning temperature is low enough; second, a lot of EVA28/150 and EVA30/30 having good compatibility with each other are obtained in the sheath and core respectively, so the sheath and core are not easy to fall off during the application. HDPE in the sheath can increase the strength of blend fibers and match to the low melting point of EVA28/150.It’s found that when the HDPE content of blends is about 15%, the spinnability of blends and the mechanical property of blend fibers are the best. Therefore, the composition for sheath of core-sheath bicomponent wig fibers is EVA28/150/HDPE blends with 15% HDPE.Bicomponent melt spinning machine is used in this study. FTIR shows that octadecane has been packed into core-sheath bicomponent wig fibers; draw temperature is 50℃, draw ratios are 2.5,3,3.5 and 4 respectively. The result shows that with the increase of draw ratio, the tensile strength of bicomponent fibers increases and elongation at break decreases; the tensile strength and elongation at break decrease with the increase of core content; when the given elongation is≤75% and the given load is≤40cN, whether it is stretched one time or five times, the core-sheath bicomponent wig fibers have good elastic recovery; with the increase of core content equivalent to the increase of octadecane, the fiber elastic recovery decreases; the phase change material will not leak out from the core-sheath bicomponent wig fibers; the content of phase change material in the fibers measured by DSC meets that of theoretical calculation; the core-sheath bicomponent wig fibers show good freeze-thaw cycle stability after experiencing 50 freeze-thaw cycles.更多还原