Toughening mechanism in polyoxymethylene/thermoplastic polyurethane blends

In order to better understand the toughening mechanism in polyoxymethylene (POM)/thermoplastic polyurethane (TPU) blends and obtain ‘super‐toughened’ POM, we carried out an investigation on the notched impact strength, fractured surface, inter‐particle distance and spherulite size of POM as a function of the TPU content. A compatibilizer, namely polystyrene‐block‐poly(ethylene–butylene)‐block‐polystyrene, grafted with maleic anhydride (SEBS‐graft‐MA), was used to enhance the interfacial interaction between the POM and TPU. The impact strength is found to increase in two steps as a function of TPU content, namely a linear increase at the very beginning, and then a jump of impact strength is seen when the TPU content is larger than 30 wt%. A ‘supertough behavior’ is not observed for POM/TPU blends at room temperature, but can be achieved after adding 5 wt% of SEBS‐graft‐MA as the compatibilizer. The impact strength was found to depend not only on the interparticle distance but also on the interfacial interactions between POM and TPU. The dependence of impact strength on crystal size is considered for the first time, and a single curve is constructed, regardless of the composition and interfacial interactions. Our results indicate that the crystal size of POM indeed plays a role in determining the toughness, and has to be considered when discussing the toughening mechanism. Copyright © 2004 Society of Chemical Industry     

再生纤维素/TPU复合膜的制备及性能研究

采用DMAC/LiCl为溶剂,分别溶解纤维素与氨纶切片TPU,强烈机械搅拌共混均匀,以蒸馏水为凝固浴制备再生纤维素/TPU复合膜,用核磁共振1 H NMR分析谱图表征了TPU的结构特征,傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、材料万能拉伸仪对复合膜的结构及强力性能进行了测试,采用WGT-S透光仪测定了复合膜的透光率,结果表明TPU引入纤维素矩阵中,一定程度上破坏了再生纤维素膜的结晶度,大大提高了再生纤维素膜的断裂伸长率,降低了其拉伸强度,当TPU加入量为20%(质量分数),再生纤维素膜的断裂伸长率提高到65%,透光率均保持良好。     

磁力电解复合抛光片的研制

根据磁力电解复合抛光对抛光片的特殊要求,本文利用TPU材料强度高、耐磨性好的特点,以TPU为基体,添加磨料和各种助剂,并对其进行微孔处理和合理配方,采用注射成型工艺,研制出了一种硬度和拉伸强度高、耐磨性和开孔性好的磁力电解复合抛光片.并且通过对不锈钢材料工件的磁力电解复合抛光试验,验证了该磁力电解复合抛光片的良好性能.     

热塑性聚氨酯/尼龙612共混体系的相互作用及结晶行为

采用溶液共沉淀法制备了热塑性聚氨酯(TPU)/尼龙(PA)612共混物,通过变温红外光谱仪和差示扫描量热仪(DSC)研究了共混体系中 TPU与PA612分子间的相互作用及其对结晶行为的影响.DSC结果表明,随着共混体系中TPU含量的增加,PA612的结晶峰温度明显降低,结晶峰宽明显变宽;相对于纯TPU,共混体系中TPU...     

A review on the mechanical and electrical properties of graphite and modified graphite reinforced polymer composites

Carbon materials particularly in the form of sparkling diamonds have held mankind spellbound for centuries, and in its other forms, like coal and coke continue to serve mankind as a fuel material, like carbon black, carbon fibers, carbon nanofibers and carbon nanotubes meet requirements of reinforcing filler in several applications. All these various forms of carbon are possible because of the element's unique hybridization ability. Graphene (a single two-dimensional layer of carbon atoms bonded together in the hexagonal graphite lattice), the basic building block of graphite, is at the epicenter of present-day materials research because of its high values of Young's modulus, fracture strength, thermal conductivity, specific surface area and fascinating transport phenomena leading to its use in multifarious applications like energy storage materials, liquid crystal devices, mechanical resonators and polymer composites. In this review, we focus on graphite and describe its various modifications for use as modified fillers in polymer matrices for creating polymer-carbon nanocomposites.     

Elastic antibacterial membranes comprising particulate laden fibers for wound healing applications

Medicated skin care products are available in various forms; ranging from lotions and creams to bandages and membranes. In this study, antibacterial particulate laden fibrous membranes (FMs) were prepared via electrospraying of tetracycline hydrochloride-loaded poly(ε-caprolactone) particles alongside electrospinning of thermoplastic polyurethane (TPU) fibers, through which both mechanical and biological aspects of a complete membrane system can be achieved. Random (R) and ordered (P and V) patterns of TPU FMs were afforded using a rotating collector. Water contact angle and bacterial inhibition zone tests were performed to assess suitability of the system specifically for wound care. Stress–strain and in vitro drug release tests were performed to assess suitability of newly developed systems specifically for hybrid membranes (HMs). The highest tensile strength (32.1 ± 4.9 MPa) with elasticity (104.2 ± 6.0%) and the most sustained release rate indicate HMs (P) are potentially suitable materials for wound-care applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47105.     

弹性体和刚性粒子对聚甲醛的增韧改性研究

采用热塑性聚氨酯弹性体（TPU）和刚性粒子纳米二氧化硅(SiO2)对聚甲醛(POM)进行了协同增韧,并通过差示扫描量热仪和扫描电子显微镜等分析了增韧体系的结构和性能。结果表明,TPU/SiO2协同增韧提高了POM缺口冲击强度,且能有效降低传统增韧方法对材料拉伸强度和弯曲模量造成的损失;当POM中单独加入20 %（质量分数,下同）TPU时,POM的缺口冲击强度提高了89 %,拉伸强度和弯曲模量却分别降低了18 %和40 %;单独加入2 % SiO2时,POM的缺口冲击强度仅提高22 %,增韧效果不明显;同时加入20 %的TPU和2 %的SiO2时,POM的缺口冲击强度提高了230 %,拉伸强度和弯曲模量仅分别下降了8 %和13 %。     

层叠状功能化石墨烯纳米带/TPU复合材料薄膜的制备与性能

利用溶液涂覆成膜工艺在涂膜机上制得层叠状功能化石墨烯纳米带（SF-GNRs）/热塑性聚氨酯（TPU）复合材料薄膜。采用FTIR、XRD、XPS、TEM和FE-SEM对SF-GNRs的结构进行表征,并结合复合材料薄膜的氧气透过率、体积电阻率测试及表面形貌观察,研究了不同质量分数的SF-GNRs对TPU复合材料薄膜阻隔和抗静电性能的影响。结果表明:所得高比表面积SF-GNRs在TPU基体中分散良好;当SF-GNRs质量分数为1.0%时,SF-GNRs/TPU复合材料薄膜的氧气透过率相比纯TPU薄膜降低了67.76%,阻隔性能得到明显改善;当SF-GNRs质量分数达到1.0%～1.5%时,SF-GNRs/TPU复合材料薄膜出现了电渗流行为,表现出优良的室温导电性能。      

热塑性聚氨酯对尼龙612熔融结晶行为的影响

用差示扫描量热法（DSC）研究了尼龙612（PA612）和聚酯型热塑性聚氨酯（TPU）共混物的熔融结晶行为。研究表明,尼龙612和TPU之间存在很强的相互作用,这种相互作用阻碍了彼此的结晶。随着TPU含量的增加,PA612的结晶度逐渐减小。PA612含量较大时,TPU本身无法结晶。两者之间的相互作用往熔融态时由于链段扩散容易显得更加明显。     

热塑性聚氨酯对尼龙6结晶行为的影响

使用X射线衍射法分析了热塑性聚氨酯（TPU）对PA6结晶行为的影响,研究了TPU软段类型。邵氏硬度对PA6的结晶行为的影响。结果表明：TPU含量越高,尼龙6的结晶度越小,但TPU邵氏硬度对结晶基本上没有影响。相同含量的TPU,随着软段分子量的提高,尼龙6的结晶度提高．即95S的TPU对尼龙6的结晶性影响最大。