NMMO工艺三元绿色复合薄膜的制备和表征

以纤维素、木质素和淀粉为原料,以N-甲基吗啉-N-氧化物(NMMO)为溶剂,制备三元天然高分子绿色复合膜。利用傅立叶红外光谱(FT-IR)和X射线衍射(XRD)测试了三元复合薄膜的结构,采用电子显微镜(SEM)和轻敲模式原子力显微镜(AFM)观察了该模型薄膜的表面形貌,并测定了薄膜力学性能。实验结果表明,三种天然高分子形成了均相的复合薄膜结构,表现出较好的力学性能和耐水性能。     

纤维素/木质素微球抗紫外薄膜制备与性能研究

随着包装工业的快速发展和人类社会对环保要求的提高,功能性且可生物降解的包装膜材料越来越受到人们的重视.然而,目前市场上的可降解包装膜材料由于成本较高、力学性能差以及耐水性低而限制了其发展.采用自组装方法制备木质素微球,并将其沉积在纤维素膜表面,制备出一种新型纤维素基抗紫外薄膜材料.通过扫描电子显微镜(SEM)、红外光谱(FTIR)和激光共聚焦电子显微镜对薄膜的表面性能进行研究.利用抗张实验和紫外透光率测试对纤维素基功能薄膜的力学性能和抗紫外性能进行表征.结果表明:自沉积木质素微球在纤维素膜表面分布均匀,尺寸为1～2μm;纤维素薄膜疏水改性后有助于木质素微球的沉积,且沉积量随着木质素质量浓度的增加而增大.由于木质素微球的引入,纤维素复合膜的抗张强度比对照样增加22％,同时其对UVB屏蔽效果可达94％.     

天然聚合物的应用与可持续发展

利用纤维素、淀粉、半纤维素和壳素、木质素、蛋白质,或者其他天然聚合物都能得到我们所需的塑料。从天然聚合物得到启发,我们可以由可再生原材料制备许多有用的新型材料,以达到可持续发展的目标。     

椰叶纳米纤维素及高强度透明膜的制备与表征

目的以农业废弃物——椰子凋落叶为研究对象,提取纳米纤维素,并用其制备高强度透明薄膜。方法采用傅里叶红外光谱(FTIR)和X射线衍射(XRD),对经酸碱处理和研磨超声提取的纳米纤维素分析表征。采用扫描电镜(SEM)、UV-紫外分光光度计和万能力学实验机,对真空抽滤的薄膜的微观形貌、透光度和力学性能进行表征。结果纳米纤维素被完整地从椰子凋落叶中提取出来,结晶度达到56%。用其制备薄膜,弹性模量达到3.3 GPa,拉伸强度达到126.4 MPa,透光度达到88%。结论椰子凋落叶可作为纳米纤维素的提取对象,并可用于制备高强度透明薄膜及其他功能型包装材料。     

聚乙二醇-碳纳米管(PEG-CNTs)共聚物膜的制备及其微摩擦行为的研究

制备了聚乙二醇接枝碳纳管共聚物(PEG-CNTs)。通过红外光谱(FT-IR)。荧光光谱(FS)和透射电子显微镜(TEM)对共聚物进行了表征。利用旋涂技术以云母为基片制备了共聚物薄膜,采用原子力显微镜／摩擦力显微镜(AFM／FFM)研究了薄膜表面的形貌及微摩擦学行为。复合薄膜内的聚合物组分保证了膜的表面平整,坚硬的碳纳米管组分增强了薄膜的承载能力。     

多糖类天然高分子/PVA可生物降解共混膜的研究进展

目的综述天然高分子(淀粉、羧甲基纤维素、壳聚糖、海藻酸钠和木质素)与聚乙烯醇(PVA)复合制备可生物降解共混膜的方法及性能的研究进展。方法分类讨论淀粉、羧甲基纤维素、壳聚糖、海藻酸钠、木质素分别与PVA进行共混制备共混膜的方法及应用。结果总结了多糖类天然高分子/PVA共混膜的研究与应用进展,并指出了该类共混膜今后发展的方向。结论多糖类天然高分子/PVA可生物降解共混膜的研究是目前科研的热点之一,该共混膜对降低环境污染和节约能源具有重要的意义,具有广阔的应用前景。     

NCC改性海藻酸钠可降解复合膜的制备及性能研究

通过硫酸水解微晶纤维素制备纳米尺寸的纤维素晶体-纳米纤维素(NCC),以NCC为增强体,通过流延法制备了纳米纤维素/海藻酸钠复合膜,采用红外光谱(FT-IR),X射线衍射(XRD)对复合膜的结构进行了表征,研究了复合膜的吸湿性能,阻隔性能,透光率及拉伸性能。结果表明:纳米纤维素可以显著提高膜的力学性能,与纯海藻酸钠膜相比,含量15%NCC使拉伸强度提高了近45%,同时NCC的引入降低了材料的吸湿率。水蒸汽透过性下降了24.9%,有效提高了材料的阻隔性能,红外光谱与XRD分析表明NCC与基体之间存在分子间氢键相互作用,具有较好的相容性。     

硅掺杂辉光放电聚合物薄膜的成分结构分析

以H2、反式二丁烯(T2B)和四甲基硅烷(TMS)混合气体为工作气体,在不同TMS流量条件下,用低压等离子体增强化学气相沉积法制备了Si掺杂辉光放电聚合物(GDP)薄膜。采用傅里叶变换红外光谱表征了不同TMS流量下Si掺杂GDP薄膜的化学组成结构。X射线光电子能谱表征了Si掺杂GDP薄膜成分,分析了TMS流量对Si掺杂GDP薄膜化学结构与元素组成的影响。研究表明:薄膜中成功地掺入了Si元素;Si掺杂GDP薄膜中Si元素主要以Si-C,Si-H等键合形式存在;在TMS流量为0.5~2 mL/min(标准状态)的范围内,薄膜中Si的原子浓度为0.72%~1.35%;随着TMS流量的逐渐增加,薄膜中Si含量逐渐增大。     

基于番茄皮渣微晶膳食纤维改性可食性膜的研究

以番茄皮渣为原料制备了微晶膳食纤维素(TMCC),并以TMCC为添加剂,采用流延法制备可食性膜;运用红外光谱(FTIR)、扫描电子显微镜(SEM)、X-射线衍射(XRD)表征TMCC的形貌和可食性膜的结晶结构,通过检测薄膜的吸湿性能、力学性能、阻隔性能和热封性能,分析TMCC对基体包装性能的影响。结果表明,在SEM图中TMCC呈50～70μm的短粗棒状,表面存在分丝纵裂现象;TMCC与可食性膜基体相容性较好,且TMCC的加入使可食性膜的结晶度增加、吸湿性降低;同时TMCC的添加有助于可食性膜力学性能、阻隔性能和热封性能的提升,当添加量约为8%时,薄膜综合性能最佳,且TMCC在高湿度条件下对材料的力学性能具有良好的保持作用。     

PVA-PEO碱性聚合物电解质的制备与表征

通过溶解-铸膜法制备了聚乙烯醇(PVA)-KOH-H2O碱性聚合物电解质膜,并向电解质中加入聚氧化乙烯(PEO)来提高离子电导率。X射线衍射(XRD)和红外光谱(FT-IR)结果表明,PEO的加入一定程度上降低了结晶度,薄膜处于无定型态。扫描电镜(SEM)表征结果显示薄膜呈非均匀网络微孔结构。交流阻抗结果表明,该薄膜室温离子电导率在mPEO/m(PVA+PEO)=0.2时达最大,为2.78×10-2S/cm。循环伏安结果表明该薄膜具有较好的电化学稳定性。     

基于体积扫描容重法的社区垃圾分类系统研究

目的 响应国家垃圾分类政策，通过设计社区生活垃圾分类设备检测系统，提高分类正确率，改善“混投乱投”的现状，从源头提高城市垃圾分类投递的准确性。方法 结合现有针对垃圾容重区间划分方法和多种评价标准，总结归纳各类垃圾的容重阈值划分区间，并将其作为垃圾分类的判断方法。设计体积检测模块，利用激光测距传感器点阵获得待测物切片遮挡图和截面积，并计算待测物体积，结合称重传感器计算待测物容重，并依据容重区间对待测物进行分类判断。结果 根据容重阈值分类标准，对多种随机样本进行检测。绝大多数可回收物和厨余垃圾的容重检测值在各分类的容重阈值内，可以被正确分类；其余样本在混合垃圾容重阈值内，符合边界条件设定和模糊垃圾的样本按其他垃圾标准处理的分选原则，检测结果符合分类要求。结论 基于体积扫描检测容重的社区生活垃圾分类系统可以满足居民前端投递环节中对生活垃圾分类检测的需求，有助于提高源头分类的准确性，能有效推进我国垃圾分类和再生资源利用工作的发展。     

淀粉基塑料购物袋性能表征研究

目的 通过对淀粉基塑料购物袋的理化性能表征,了解淀粉基塑料购物袋使用特性,为改善淀粉基塑料购物袋使用性能提供一些理论依据。方法 采用热重分析(TG)、热机械分析(TMA)等手段对淀粉基塑料购物袋的淀粉含量及耐热性能进行分析,借助电子万能材料试验机对淀粉基塑料购物袋的力学性能进行分析,以及利用霉菌培养、总迁移行为探究等方法对淀粉基塑料购物袋霉变程度、卫生性能进行分析。结果 样品A、B、C淀粉质量分数分别为15.72%、23.97%、30.36%,耐热性能比传统PE塑料袋要低;淀粉基塑料购物袋的拉伸强度随淀粉含量的增大而减小,断裂伸长率随淀粉含量的增加而增加,总迁移量结果随淀粉含量增加而增大,但经三氯甲烷处理后均低于限量要求;淀粉基塑料购物袋不适宜盛装酸性和低乙醇类食品。结论 通过对淀粉基塑料购物袋深入研究,发现淀粉基塑料购物袋在力学性能、总迁移量、霉变程度存在缺陷,望研究者们可以从这几个方向入手,改善淀粉基塑料购物袋的理化性能。     

绿豆芽可食性膜的制备及性能研究

以绿豆芽为基材,羧甲基纤维素和海藻酸钠作为成膜剂,甘油为增塑剂,通过正交试验,优化可食性膜的配方,并进行了膜性能的测定。 结果表明,配方最优组合为绿豆芽浆料 20. 0 g、羧甲基纤维素 1. 5 g、海藻酸钠1. 8 g、甘油 1. 5 mL,经过测定,膜综合性能良好。 绿豆芽可食性膜食用方便,增加了营养,同时又保护了环境,具有广阔的发展前景。     

电动热封口式垃圾桶的设计

为避免垃圾桶中的垃圾直接与人体接触,减少垃圾对环境的污染,基于电动热封口技术,设计了一种电动热封口式垃圾桶。以MSP430单片机为控制核心,采用梯形丝杠传动技术,将步进电机的转动转换为垃圾桶压条装置的直线运动;在压条装置上辅以合理的电路设计以及双层电热丝结构,实现对塑料垃圾袋无间隙、低噪音封口;选用LCD12864液晶显示器和语音模块,用文字和声音实时显示封口过程。设计了垃圾桶的封口单元和电动热封口控制单元,进行了塑料垃圾袋的封口实验。实验结果表明,选用PE （polyethylene,聚乙烯）材质垃圾袋和Cr20Ni80电热丝能够快速准确地实现电动热封口。研究结果对垃圾桶的绿色设计和智能化设计具有重要的参考价值。     

Effect of starch-based biomaterials on the <Emphasis Type="Italic">in vitro</Emphasis> proliferation and viability of osteoblast-like cells

The cytotoxicity of starch-based polymers was investigated using different methodologies. Poly-L-lactic acid (PLLA) was used as a control for comparison purposes. Extracts of four different starch-based blends (corn starch and ethylene vinyl alcohol (SEVA-C), corn starch and cellulose acetate (SCA), corn starch and polycaprolactone (SPCL) and starch and poly-lactic acid (SPLA70) were prepared in culture medium and their toxicity was analysed. Osteoblast-like cells (SaOs-2) were incubated with the extracts and cell viability was assessed using the MTT test and a lactate dehydrogenase (LDH) assay. In addition DNA and total protein were quantified in order to evaluate cell proliferation. Cells were also cultured in direct contact with the polymers for 3 and 7 days and observed in light and scanning electron microscopy (SEM). LDH and DNA quantification revealed to be the most sensitive tests to assess respectively cell viability and cell proliferation after incubation with starch-based materials and PLLA. SCA was the starch blend with higher cytotoxicity index although similar to PLLA polymer. Cell adhesion tests confirmed the worst performance of the blend of starch with cellulose acetate but also showed that SPCL does not perform as well as it could be expected. All the other materials were shown to present a comparable behaviour in terms of cell adhesion showing slight differences in morphology that seem to disappear for longer culture times.The results of this study suggest that not only the extract of the materials but also their three-dimensional form has to be biologically tested in order to analyse material-associated parameters that are not possible to consider within the degradation extract. In this study, the majority of the starch-based biomaterials presented very promising results in terms of cytotoxicity, comparable to the currently used biodegradable PLLA which might lead the biocompatibility evaluation of those novel biomaterials to other studies.     

Arabinoxylan/nanofibrillated cellulose composite films

There is an increasing interest in substituting petroleum based polymer films, for food packaging applications, with films based on renewable resources. In many of these applications, low oxygen permeability and low moisture uptake of films are required, as well as high enough strength and flexibility. For this purpose, rye arabinoxylan films reinforced with nanofibrillated cellulose was prepared and evaluated. A thorough mixing of the components resulted in uniform films. Mechanical, thermal, structural, moisture sorption and oxygen barrier characteristics of such films are reported here. Reinforcement of arabinoxylan with nanofibrillated cellulose affected the properties of the films positively. A decrease in moisture sorption of the films, as well as an increase in stiffness, strength and flexibility of the films were shown. From these results and dynamic FTIR spectra, a strong coupling between reinforcing cellulose and arabinoxylan matrix was concluded. Oxygen barrier properties were equal or better as compared to the neat rye arabinoxylan film. In general, the high nanofibrillated cellulose containing composite film, i.e. 75 % NFC, showed the best properties.     

Investigation of the graft length impact on the interfacial toughness in a cellulose/poly(ε-caprolactone) bilayer laminate

Interfacial adhesion between immiscible cellulose-polymer interfaces is a crucial property for fibrous biocomposites. To tailor the interfacial adhesion, the grafting of polymers from cellulose films was studied using ring-opening polymerization of ε-caprolactone. The poly(ε-caprolactone) (PCL) grafted cellulose was analyzed with FTIR, AFM and via water CA measurements. The graft length was varied by the addition of a free initiator, enabling tailoring of the interfacial toughness. Films of microfibrillated cellulose were grafted with PCL and hot-pressed together with a PCL-film to form a bilayer laminate. Interfacial peeling toughness correlates very strongly with PCL degree of polymerization (DP). PCL grafts form physical entanglements in the PCL matrix and promote significant plastic deformation in the PCL bulk, thus increasing interfacial peeling energy.     

Rational development of a unique family of renewable polymers

A unique family of renewable polymers has been constructed through facile chemical and physical approaches. In viewing of the abundant and renewable characteristics of starch, cellulose, chitosan and alginate, they are adopted as starting materials. Lactic acid and carbon dioxide, which can be regarded as derivates of starch, are also adopted as starting materials since both of them are abundant, non-toxic and renewable. For sake of making the intension to be carried out easily, the applied chemical or physical approaches are as facile as possible. After two decades of effort, a variety of polymers with versatile properties such as improved mechanical strength, good adsorption or loading capacity and various intelligent behaviors have been tailor-made. These polymers are designed systematically instead of obtaining at random. Herein, our ideas and the strategies for developing the polysaccharide-based renewable polymers are elucidated. It is expected that what presented in this article could stimulate more ideas to develop renewable polymers and bring brighter prospect of the polysaccharide-family.     

Binderless all-cellulose fibreboard from microfibrillated lignocellulosic natural fibres

Fully biobased all-cellulose fibreboards are produced without the use of additional bonding agents such as polymer resins or binders as in the case of e.g. medium density fibreboard (MDF) or natural fibre reinforced plastic (NFRP). These materials make use of the self-binding capability of cellulose, exploiting the enhanced hydrogen bonded network present in micro- and nanofibrillated cellulose, resulting in good mechanical performance. After the optimisation of refinement, drying and hot-pressing conditions, binder-free panels from microfibrillated flax fibres with excellent mechanical properties of around 17 GPa and 120 MPa for flexural modulus and strength, and relatively low water sorption are achieved, making these materials competitive with conventional cellulose based composite materials. The work shows the potential of creating all-cellulose engineering materials using only the intrinsic bonding capacity of microfibrillated lignocellulose, potentially leading to environmentally friendly panel board materials, which are entirely based on renewable resources, recyclable and biodegradable.     

Outstanding Toughness of Cherry Bark Achieved by Helical Spring Structure of Rigid Cellulose Fiber Combined with Flexible Layers of Lipid Polymers

Cellulose, a main component of cell walls, generally makes materials hard and brittle. However, an ultratough, cellulosic material is found in nature: cherry bark. Surprisingly, it elongates by more than twice of its initial length and behaves as a plastic film during stretching. This amazing mechanical property is achieved by a well‐designed cell wall structure; cellulose fibers are folded like helical springs, covered by multiple flexible layers of lipid polymers.