二醋酸纤维素纤维纺丝溶液的动态黏弹性

 采用Physica MCR101流变仪考察了二醋酸纤维素（CDA）纺丝溶液浓度和温度对其动态黏弹性的影响。结果表明：在一定的角频率下,随着CDA纺丝溶液浓度的升高或温度的降低,体系的储能模量（G/）、损耗模量（G//）和复数黏度（η*）均呈现增加趋势,但损耗角正切（tanδ）逐渐降低。并且发现浓度为27.8%或者温度为59℃的CA纺丝液,随着角频率的增加,体系的G/、和G//相应增加,而tanδ和η*则随之降低。关键词 二醋酸纤维素; 动态黏弹性; 储能模量; 损耗模量; 损耗角正切; 复数黏度     

An electroencephalogram study on softness cognition of silk fabric hand

Fabric hand is a comprehensive sensation when fingers touched the fabrics, and it is an important index in evaluating the comfort of clothes. In this study, electroencephalogram (EEG) method was used to record the brain potentials when people touched and evaluated the fabrics for softness sensation, compared with subjective assessment and physical indicators tested by KES, the results show that Alpha wave’s power and the activity area of Alpha rhythm had significant positive correlation with subjective evaluation and physical indicators of fabric softness sensation.     

织物柔软度的等级划分

针对织物柔软性评价体系不够完善的问题,探讨织物柔软度的量化以及柔软度的等级划分。采用主客观评价相结合的方法建立30块柔软度存在差异、且有较宽分布的机织物样本空间,利用主成分分析的方法计算这些样本的12项力学指标的综合评价值,并以此综合评价值作为量化评价织物柔软度的依据。再按综合评价值由小到大的顺序将样本均分为6个等级,结合主观评价对分级区间样本进行微调,得到以综合评价值为基础划分的织物柔软度的6个等级区间,并验证了结果的合理性与客观性。     

织物柔软性的主客观评价

针对目前织物柔软性评价方法不够完善的问题,探讨织物柔软性的主观和客观评价方法。主观评价方法选择秩位法;客观评价方法借助KES-F织物风格仪测试与织物柔软性有关的弯曲性能指标、剪切性能指标和压缩性能指标共7个力学指标作为评价指标,运用主成分分析方法,得出影响织物柔软性的显著因素,进而得到综合评价值,由综合评价值的大小对织物柔软性的优劣进行排序。通过比较发现客观评价得到的结果与主观评价结果有较好的一致性,客观评价较主观评价更为严密可靠。     

纱线的动态力学性能

纱线的力学性能在很大程度上影响着织物的力学性能和耐用性,因此对纱线力学性能的研究,尤其是对纱线在动态拉伸情况下的动态力学性能的研究是十分重要的。应用美国劳森公司的CTT纱线性能测试仪,对纱线的动态力学性能进行了研究分析,通过测试发现,纱线的动态力学性能指标比静态测试的力学指标更能全面真实地反映纱线在织造过程中的实际受力情况和力学性能。     

亚麻纱线的柔软处理

探讨了采用纤维素酶对亚麻纱线预处理,再使用柔软剂进行柔软处理来降低亚麻纱线刚度的方法。结果表明此方法可明显降低亚麻纱线刚度,提高纯亚麻纱线的上机编织效果,且使用酶剂不会对环境造成污染,有利环保。     

Relationship between perceived softness of bilayered skin models and their mechanical properties measured with a dual‐sensor probe

The development of a sensor system that can predict the subjective softness of human skin is an important goal for the cosmetics industry. Here, we first carried out a subjective softness evaluation test using 65 skin models consisting of polyurethane bilayers with different thickness of the superficial layer and different degree of cross‐polymerization of the basal layer. The results showed that perceived softness was dependent on the mechanical properties of both the superficial and basal layers. Then, we used a recently developed tactile sensor system composed of a piezoelectric tactile sensor and a load cell to measure mechanical softness parameters of the superficial layer and the whole model, respectively. Statistical analysis showed that the data obtained from these two sensors were well correlated with the perceived softness of the prepared models. These results suggest that it may be feasible to predict the subjective softness of human skin in vivo from non‐invasive mechanical softness measurements of the superficial skin layer and whole skin obtained with our new dual‐probe sensor system.     

二醋酸纤维的动态力学性能

利用动态力学分析(DMA)研究不同含水率的二醋酸纤维的动态力学性能,分析二醋酸纤维的各种松弛类型及其机制。研究表明:二醋酸纤维的玻璃化转变温度为184℃左右,在玻璃化转变温度以下,其β*和γ松弛与纤维的含水率有关。β*松弛很可能是由结合水分子的羟基和水分子的协同运动引起;γ松弛是由与未酯化羟基松散结合的水分子运动而导致;较宽的β松弛峰同样也存在于纤维素DMA温度谱中,主要是由纤维素主链的局部曲柄运动引起的,但也不排除侧基和吡喃环协同运动的可能性。     

卫生纸柔软度的测定及不确定度评估

探讨了在质检过程中卫生卷纸试样的尺寸大小与柔软度测定结果的比例对应关系，并进行柔软度测量过程中的不确定度评定。     

Dynamic mechanical analysis and creep-recovery behavior of agglomerated cork

The mechanical behavior of agglomerated cork, made of cork granules bound with polyurethane moisture-cured adhesive is investigated and compared to natural cork in the small strain regime (strain?<5%). Dynamic mechanical analysis (DMA) of the agglomerated material revealed two distinct thermal transitions, one at ?45?°C, related to the glass transition of polyurethane, and one at 3?°C, associated with melting of suberin, a natural polyester that is the main component of cork’s cell walls. Natural cork showed the latter transition to occur at a higher temperature range, between 10 and 25?°C, probably due to a different crystalline arrangement being formed upon cooling the cork granules under pressure in the mold. The storage modulus of agglomerated cork was found to be similar to that of natural cork. Creep and recovery experiments were well described by Burgers model and Weibull distribution function, respectively. Agglomerated cork showed higher instantaneous creep strain and viscous flow than natural cork, probably due to relative displacement and slippage of the granules being allowed by the binder. In all cork materials, not all the instantaneous creep strain was instantaneously recovered. A fraction underwent delayed recovery and another turned into permanent strain. This behavior was associated with the deformation of corrugations in the cork cell walls. Cyclic creep-recovery tests showed for all cork materials recoveries above 90%, except for the first cycle.     

热塑性弹性体增韧薄膜防水复合面料黏弹性的表征研究

通过热重分析方法对最新研发的热塑性弹性体(TPE)增韧薄膜防水复合面料的黏弹性能及主要的应用性能进行了测试研究分析,认为用TPE可以替代被限制使用的PVC背胶.     

热处理对山羊绒、兔绒、驼绒纤维力学性能的影响

选择山羊绒、兔绒、驼绒3种绒类纤维,分别在常温干、湿态和经过干热处理后进行拉伸力学性能测试,结果表明:湿处理对兔绒的力学性能影响最大;热处理对驼绒的力学性能影响最大;热处理对兔绒和驼绒的力学性能影响比湿处理影响大.     

Dynamic mechanical characterization of mechanosorptive effects in wood and paper

Dynamic mechanical studies in dual cantilever and tensile stretching mode of Scots pine veneer, birch veneer and paper under stepwise humidity changes between 5% and 85% relative humidity are reported. The loss tangent (tanδ) shows a transient peak every time the relative humidity of the surrounding atmosphere is changed. In the bending mode a clamping arrangement that is freely movable in the longitudinal direction gives more distinct damping peaks than does a static fixture. There is a close relationship between the rate of sorption/desorption and the shape of the tanδ peak. In response to reduction of the rate of humidity change the damping transients slowly disappear. They also diminish in strength as the temperature is raised toward 60°C. Their strengths increase as the measuring frequency is lowered toward 0.01 Hz. Also, when the samples are highly compressed or prestressed with static loads the peak heights are greatly reduced. The tanδ peaks become less distinct and eventually disappear when the amplitude of the vibration increases. Long time testing results in significant changes in the shapes of the tanδ versus time data. A working hypothesis is that these phenomena are closely related to molecular diffusion of water through the sample material. Simple estimates show that the relaxation time for a diffusion related process should be of the order of a minute.     

皮革丰满性和柔软性测定原理及方法的研究

对皮革丰满性和柔软性的测定原理及方法进行了探讨.现行实施的对皮革的评定是主观的,为了评价皮革的丰满柔软性,设计并制作了一种皮革顶伸性能测定仪,通过压缩和顶伸试验,用易于测定的参数压缩功Wcp、回弹功Wcr和顶伸功Wf等来确定皮革的丰满性和柔软性,分析结果与手感检测相一致.     

医疗卫生用非织造材料柔软性测试方法分析

介绍医疗卫生用非织造材料的柔软性测试方法,分别采用主观评价法、Handle-O-Meter测试法和单面压缩测试法对10块非织造材料试样进行柔软性测试,并进行相关性分析,结果显示:单面压缩测试法与主观评价法相关性最大,单面压缩测试法更适合替代主观评价法用于非织造材料柔软性的测试。     

发软泡菜品质及风味物质主成分分析

以软化的泡萝卜为研究对象,探究正常泡菜和不同发软程度泡菜的理化性质及风味物质的差异,采用顶空固相微萃取—气相色谱—质谱联用技术(headspace solid-phase microextraction-gas chromate graphy-mass spectrometry,HSSPME-GC-MS)对风味进行测定并进行主成分分析。试验结果显示,正常泡菜的质构指标、感官品质均优于发软泡菜,发软泡菜酸度、盐度高于正常泡菜,4种泡菜均呈黄绿色调。正常泡菜与3种不同程度发软泡菜中分别检测出41,32,37,30种挥发性成分。二甲基三硫是区分正常泡菜与发软泡菜的风味物质,严重发软泡菜特有的风味物质是乙醛二甲基硫缩醛,其相对含量为32.09%。随着发软程度的加深,泡菜品质逐步下降。     

In vivo measuring of skin softness using the Gas Bearing Electrodynamometer

The bio-mechanical properties of the stratum corneum are of great importance for the subjective perception of skin conditions (dry vs. normal), as well as for its multiple functions. The recently developed Gas Bearing Electrodynamometer allows us to measure objectively the viscoelastic properties of the stratum corneum in vivo and to evaluate, in terms of skin softness, the changes of this parameter induced by the application of emollients.
The principle of the technique, as designed by Christensen et al. , is briefly described in context with our results.
During the probe movement, there was a modification of the skin surface relief: compression of the skin furrows ahead of the moving probe, and extension-flattening of the relief behind the probe.
The variations of the skin softness were studied in context with the reproducibility of the measurements: the coefficient of variation was found to be about 3%. Considerably higher variations were found as related to: the anisotropy of the skin surface relief, various areas of the body, and individual differences.
The effects of emollients and water on the skin softness were studied. Water had a clear effect but of very short duration (around 10 minutes). Water-containing emollients of the type o/w emulsions displayed a distinct long-lasting effect (followed up to 6 hours). Its magnitude was generally higher than that obtained with w/o emulsions. It was found that the emollient's non-volatile components (oil phase) play an important role in the product's softening effect.
In conclusion, results to date have established this technique as a promising tool for studying skin softness in general, and effects of topical applications, new formulae and specific ingredients in particular.
Mesure de la souplesse de la peau avec un Electrodynamomètre