生物基可降解聚合物食品包装材料发展及应用综述

目的 介绍生物基聚合物包装的研究进展,总结生物基聚合物包装材料的功能化。方法 综述目前生物基聚合物包装材料来源的分类,列举天然生物基聚合物、微生物合成的生物基聚合物和化学合成的生物基聚合物在食品包装方面的研究进展,总结生物基聚合物包装材料的功能化方向(抗菌、抗氧化、pH响应、光热响应等)。结论 生物基聚合物食品包装在绿色食品包装领域有较好的应用潜力。     

超高压保鲜包装技术的研究进展

目的研究超高压保鲜包装技术的保鲜机理、现状和未来的发展方向。方法超高压技术(UHPP)是一种新型的非热加工技术,它主要通过破坏微生物的细胞壁、细胞膜及细胞间隙的结构,使蛋白质等成分发生变性,使酶活性降低来达到杀菌的目的。从超高压技术在水产品工业、肉制品工业及果蔬、其制品工业等方面,阐述了超高压杀菌技术的应用现状及进展。结论超高压保鲜包装技术还处于起步阶段,目前的研究主要集中在技术工艺方面,对于保鲜机理的研究相对较少。随着对超高压保鲜包装技术研究的不断深入,关于其相关机理的研究会越来越深入。     

Mechanical Characterisation of a New Biodegradable Film

Abstract: Plastics are utilised in almost every manufacturing industry in the world because of the favourable balance of mechanical, technological and cost factors. However, to minimise the environmental impact of plastic materials, researchers are attempting to synthesise new biodegradable polymers that can satisfy also standard requirements on manufacturability and mechanical properties. This paper studies a new material where an aliphatic–aromatic biodegradable component is included in a polyester matrix. For that purpose, microbiological tests, manufacturability tests and mechanical tests are carried out. In particular, thin films are exposed to the attack of spore colonies to check if the new material is fully biodegradable and compostable. Material formability in fashion of blown films is investigated for different volume fractions of biodegradable component added into the formula. Mechanical behaviour of the new material is then assessed by carrying out tensile tests. Experimental results demonstrate that thin films of the new material can be produced using the standard technologies currently available. Mechanical properties are better than those possessed by traditional non‐biodegradable plastics like polyethylene.     

The Use of Scanning Transitiometry to Investigate Thermodynamic Properties of Polymeric Systems over Extended T and p Ranges

Scanning transitiometry is a newly developed technique in which one of the independent variables (p,V, or T) is scanned in the working cell of a very sensitive calorimeter while the other independent variable is kept constant. The change of the dependent variable is recorded simultaneously with the thermal effect associated with the process or the system under investigation. In the case of non-reacting systems which remain in a homogeneous state, both the mechanical and thermal outputs thus obtained give straightforward access to pairs of thermomechanical coefficients: _p and _T , _V and _T , C _p and _p , C _V and _V , depending on the pair of selected independent variables. When the system or the material sample goes through a chemical reaction or a phase change, the recorded information yields the corresponding heat and pVT characteristics. The working cell may also house an optical fiber probe for spectrophotometric in situ readings from UV to NIR, as well as injection and stirring devices permitting investigation of reacting systems. The actual operating ranges of current scanning transitiometers are 173K<T<673K and 0.1<p<200MPa (or 400MPa). With such equipment, bulk properties, phase transitions, and reactions (i.e., polymerization) can be advantageously studied. Selected examples, all dealing with polymeric systems (including biopolymers), are illustrated, namely, measurements of thermomechanical coefficients (thermal expansion, compressibility), characterization of transitions (fusion, crystallization, glass transition, gelatinization) and particle synthesis. All examples show that scanning transitiometry is a versatile technique that can be used to fully characterize thermophysical properties as well as the thermodynamic behavior of a large variety of systems and materials.     

微纳米多孔聚合物在食品包装和检测中的应用

目的系统介绍微纳米多孔聚合物的制备及其在食品包装和检测方面的应用。方法以文献调研为主,分析目前食品行业所用微纳米多孔聚合物的基材和制备加工方法,及其在食品行业中的应用。结果微纳米多孔聚合物可以和活性包装技术、食品检测技术相结合,既可以直接作为包装材料,也可以负载检测试剂或生物传感器等,在食品行业有很多独特的应用,开发多孔聚合物的更多功能和应用,提高制备加工技术,制造和使用过程生态化是今后研究的重点。结论微纳米多孔聚合物因其独特的结构和功能,在今后的食品行业有很广阔的应用前景。     

超高压杀菌处理对包装材料稳定性的影响

在超高压条件下对PET/AL/PE和PET/VMPET 2种塑料薄膜进行处理,测定不同压强及保压时间对材料拉伸强度、断裂伸长率、热封性能及阻隔性能的影响。结果表明:超高压对2种材料拉伸强度及断裂伸长率均未表现出显著影响,但对PET/VMPET/PE材料的热封强度影响显著;在500 MPa压强下保压时间对2种材料的透湿性能影响显著。     

国外软包装材料的现状及研发方向

论述了国外塑料软包装材料的种类,功能化包装的类型,及其当前在包装和包装材料领域主要的研发方向.软包装材料目前逐步向环境友好、高阻隔、纳米复合等方向发展;包装类型走向功能化、智能化;除上述主要的研发方向外,包装材料的助剂迁移对食品安全的影响也是目前的研究热点.     

气压调节阀的作用及原理探讨

对低压状态下包装容器密封失效进行了分析,对比介绍了国内外气压调节阀研究应用现状,并提出了两种气压调节阀工作原理     

燃料喷嘴口微孔的几何与表面表征

燃料喷嘴口的微孔在汽车发动机的燃料效率和尾气排放中起关键作用．微孔的几何与表面质量的表征对理解其制造过程及其对喷嘴功能的影响十分重要,然而由于其尺寸小,对这类微孔质量的表征一直是一个难题．本文介绍作者最近进行的用扫描电子显微镜、扫描隧道显微镜、原子力显微镜来表征微孔质量研究的一个实例．虽然大多数计量系统并不是为测量像喷嘴口的微孔这类非平面特征设计的,只要合理选择装置和测头,微孔的高精度多尺度表征是可以实现的．     

多孔陶瓷薄膜表面形貌研究

用原子力显微镜（ＡＦＭ）观察Ａｌ２Ｏ３、Ａｌ２Ｏ３－ＳｉＯ２及Ａｌ２Ｏ３－ＳｉＯ２－ＴｉＯ２复合陶瓷薄膜的表面形貌,Ｘ射线衍射（ＸＲＤ）分析表明,Ａｌ２Ｏ３薄膜的上为γ－Ａｌ２Ｏ３;Ａｌ２Ｏ３－ＳｉＯ２薄由γ－Ａｌ２Ｏ３和非晶诚ＳｉＯ２组成;而Ａｌ２Ｏ３－ＳｉＯ２－ＴｉＯ２薄膜的相成分为Ａｌ２Ｏ３、ＴｉＯ２、Ａｌ４Ｔｉ２ＳｉＯ１２和非晶态ＳｉＯ２,各相的含量随化学成分变化而变化,ＡＦＭ观察结果表明     

超高压处理对食品包装材料的影响研究进展

超高压杀菌处理对食品品质的影响较小,能较好地保持食品原来的营养和风味。阐述了超高压处理的杀菌机理及影响因素,综述了超高压处理对食品包装材料的机械性能、阻隔性能、物质迁移的影响研究状况,展望了超高压处理对食品包装材料影响研究的发展方向。     

蓄电池塑料箱自动缠膜包装机设计

目的 针对蓄电池外壳塑料箱贮存、物流运输过程中出现的粉尘污染、破损等问题,在注塑成型后,需经覆膜处理。由于蓄电池外壳较薄,热缩工艺防护手段变形严重,对产品质量产生较大影响,迫切需要设计一种高效、便捷的蓄电池外壳防护包装工艺。方法 依据功能模块化设计理念提出托盘式塑料箱缠膜的解决方法,针对缠膜包装制定了集整形、缠膜、物料输送为一体的塑料箱自动缠膜工艺和各功能模块机械系统设计,并通过数字化手段验证工艺的合理性。结果 该设备实现了对多种规格的蓄电池外壳塑料箱的整形、缠膜、物料输送一体化生产,效率达到42s/件,相较于人工方式的效率提升了1.4倍。结论 该设备结构合理,在保证缠膜包装质量的前提下,提高了缠膜包装效率,推动了企业自动化进程,为塑料箱自动缠膜包装提供了解决方案。