The Potential of NanoCellulose in the Packaging Field: A Review

Nanocellulose has potential applications across several industrial sectors and allows the development of innovative materials, as well as the enhancement of conventional materials properties. The nanocellulose particles can be utilized as fillers, in composites manufacture, as coating and as self‐standing thin films, achieving always very interesting and promising properties. Very few of the several reviews that recently appeared on this topic in the scientific literature, however, summarized the potential of cellulose in nanoform specifically for the packaging field rather focusing on different aspects, ranging from the chemistry and the morphology of nanocellulose particles to the preparation methods, the industrial applications and the patents released. In the present review, the remarkable chemical and physical properties of nanocellulose are introduced and discussed with specific reference to the packaging needs. First, the cellulose resources and structure are introduced, then the process methods to reach the nanoscale, the corresponding morphologies and nomenclatures are summarized, mentioning also the possible chemical modifications of nanocellulose and, finally, its practical and potential applications for packaging materials, especially food packaging materials, are tentatively proposed and discussed. Although the review might not cover every aspect on nanocellulose, yet the key points, particularly those related to safety and biodegradability issues, are regarded and considered. Copyright © 2015 John Wiley & Sons, Ltd.     

等通道转角挤压制备超细晶材料的研究与发展

等通道转角挤压(Equal channel angular pressing,ECAP)是大塑性变形制备超细晶材料的方法之一,具有大晶粒尺寸的材料可以在室温下挤压达到超细晶尺度。从ECAP模具参数、工艺条件影响因素、模具及制备方法改进、细化机理、制备的超细晶材料组织稳定性及性能方面进行总结,并结合部分研究结果可知,ECAP模具正在不断被优化和改进,复合挤压技术不断出现,目前已实现超细晶材料的连续ECAP挤压制备技术。等通道转角挤压的晶粒细化主要是由于剪切力的作用和第二相粒子的作用,ECAP晶粒细化机理及组合工艺的研究是目前研究的热点。超细晶材料在不同领域的应用对其性能提出的更高要求,对其大塑性变形制备技术本身也是挑战。     

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。     

功能性食品包装材料的研究进展及发展趋势

目的介绍国内外功能性食品包装材料的最新研究进展,指出目前食品包装存在的问题,阐述未来功能性食品包装材料的发展趋势。方法总结国内外不同功能的食品包装(智能包装、抑菌包装、阻隔包装、乙烯吸附及释放包装、生物可降解包装等)的研究现状,简要介绍不同功能食品包装的组成、制备以及应用。结果不同功能性的食品包装在食品的贮藏、保鲜、品质监测等方面发挥着重要作用。由于目前食品包装的功能较为单一、包装材料缺乏环保性且成本较高,难以商业化应用,因此开发环保、价格低廉的多功能性复合包装在食品品质保障方面具有重要意义。结论开发绿色、环保的多功能复合包装材料应用于食品保鲜、品质监测具有广阔的发展前景。     

Cellulose Nanocrystals from Lignocellulosic Raw Materials,for Oxygen Barrier Coatings on Food Packaging Films

Cellulose nanocrystals (CNCs) are unique, renewable top‐down nano particles from which coatings with improved gas barrier properties and new functionalities can be prepared. In this paper, the potential for obtaining such high performing nanocrystals from low‐cost lignocellulosic by‐products or raw materials is proved by a comparison study on CNCs obtained both from cotton linters and kraft pulp, by means of the ammonium persulfate (APS) process. Morphological and chemical characterization of the nanocrystals obtained, as well as the main functional properties of the poly(ethylene terephthalate) coated films, showed quite similar characteristics and performances of CNCs obtained from pure cellulose raw material (cotton linters) and the nanoparticles produced from a potential discard of paper making processes (kraft pulp). In particular, the gas barrier properties of the coating produced with CNCs obtained from kraft pulp were very promising, providing oxygen and carbon dioxide permeability values hundreds of times lower than those of equal thickness in comparison with common barrier synthetic polymers, over a broad range of temperatures. The results obtained are relevant not only for the outstanding performances achieved, but also because they evoke a possible positive example of industrial symbiosis in the packaging field, merging together the requirements and needs of the paper and plastic industries and addressing the way towards a better management of waste and materials. Copyright © 2017 John Wiley & Sons, Ltd.     

Migration of Photoinitiators in Food Packaging: A Review

Photoinitiators are highly photoactive compounds included in the formulations of UV curing printing inks and varnishes. Twenty five of those photoinitiators can be found in the bibliography regarding food packaging migration and analytical methods with an increasing interest in the last 9 years because of the foodstuffs contamination with 2‐isopropylthioxanthone detected in 2005. An overview about migration of photoinitiators in food packaging is firstly given in terms of Rapid Alert System for Food and Feed notifications, mechanisms of migration, and specific migration limits. Besides set off, a migration model based on diffusion and partition coefficients is considered to analyse the factors affecting migration: physicochemical properties of the photoinitiator, characteristics of the foodstuffs and food simulants, temperature and packaging. Molecular weight, volatility, polarity and lipophilicity are considered as the main physicochemical properties of the photoinitiators playing a role in migration. In relation with the food packaging, information from published works is reviewed, taking into account the special migration behaviour of paper and cartonboard as well as the efficiency of different plastic films as barriers to avoid or reduce migration. Results of the application of the migration model are compared with reported data from the bibliography. Finally, the use of polymeric multifunctional photoinitiators is concluded as the best option for ultraviolet curing inks and varnishes to print food packaging. They have higher molecular weight together with fewer and lower volatility photodecomposition byproducts and a higher probability than conventional photoinitiators of being bound into the cured polymer matrix. Copyright © 2014 John Wiley & Sons, Ltd.     

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。     

改性聚酯涂层的制备及在食品包装材料中的应用

目的 制备改性聚酯涂层,解决纯聚酯涂层与基材润湿性较差,导致涂层出现附着力差、缩孔等问题,获得综合性能优异的镀锡板食品包装用新型涂层材料。方法 以二元酸、二元醇为原料,通过缩合聚合方法合成聚酯树脂,用双酚F型环氧树脂化学改性聚酯树脂,制备环氧改性聚酯树脂,并用氨基硅烷作为固化剂构筑硅烷化环氧改性聚酯涂层。通过GPC、FTIR、TGA、OM、WCA、附着力等分析、考察硅烷化环氧改性聚酯树脂涂层与常规氨基树脂固化环氧改性聚酯涂层的性能差异。结果 通过性能对比发现,树脂与硅烷固化剂质量比为3∶1时,mEster 1.0和mEster 1.1涂层样品综合性能最佳,涂层在镀锡板基材表面润湿性好,缩孔等缺陷少,耐水煮性好,铅笔硬度为2H,丙酮擦拭50次后表面仍完好,分解温度在250℃以上。结论 硅烷化环氧改性聚酯树脂涂层中低表面自由能的Si-O-Si键对其性能提升有关键作用,该涂层可应用于镀锡板等金属基材食品包装保护材料。     

食品包装用壳聚糖薄膜的研究进展

目的旨在通过系统综述壳聚糖性质、壳聚糖薄膜制备方法,以及壳聚糖薄膜在食品包装上应用的国内外研究成果,为开发可降解性、抗菌性、抗氧化性、阻隔性能以及力学性能均较优秀的壳聚糖食品包装膜提供方法指导。方法综述壳聚糖性能特点、壳聚糖食品包装膜的制备工艺和影响壳聚糖食品包装膜性能的各种因素,重点探讨国内外壳聚糖食品包装的研究现状。结果向成膜配方中添加蛋白类、酚类以及其他天然提取物等助剂,可改善壳聚糖复合膜的物理力学性能、阻隔性能、抗氧化性能以及抗菌性能。结论壳聚糖基于自身的可降解性和抗菌性,在食品包装膜领域具有良好的发展和应用前景,但就目前的研究成果以及壳聚糖复合膜实际应用过程中出现的问题来说,壳聚糖食品包装膜在生产工艺、综合性能等方面还有待提高。     

Nanostructuring and Microstructuring of Materials from a Single Agropolymer for Sustainable MAP Preservation of Fresh Food

The main objective of the present work was to determine whether a single agropolymer [wheat gluten (WG)] could fit the modified atmosphere packaging (MAP) requirements of a range of six different fresh produce in key terms of oxygen permeation (Pe_O2) and CO₂/O₂ permselectivity (S) values. The required properties for optimal packaging of fresh fruits and vegetables were first evaluated using the Tailorpack MAP modelling software (UMR IATE, Montpellier, France) with packaging dimensions and respiratory and optimal atmosphere data as input parameters. Then, the modelled values obtained were compared with the properties of a range of WG composite films: monolayer self‐supported or multilayer at microscale or nanoscale, cast or thermoplasticised, with different formulations (percentage of plasticisers or nanofillers). The experimental gas transfer properties that could be covered by these materials ranged from 0.05 × 10^?10 to 2.00 × 10^?10 mol/m² s Pa for Pe_O2 and up to 18.0 for S. These ranges are much larger than conventional plastics that exhibit Pe_O2 from 0.10 × 10^?10 to 0.20 × 10^?10 mol/m² s Pa and S up to 4.5. It was demonstrated from a food‐requirements‐driven (Tailorpack modelling) and a multiscale film structuring (WG‐based composites) approaches, that transfer properties of WG‐based films would fit the requirements of the six selected fruits and vegetables better than conventional plastics. Copyright © 2012 John Wiley & Sons, Ltd.     

提高食品包装材料安全性的途径

食品包装材料迁移引起的食品安全危害日趋突出.国家有关部门应当进一步完善食品包装材料的安全性标准,建立科学的食品包装材料安全体系,实施良好的生产管理规范,严格市场准入制度和监管机制,并在此基础上,应用新型环保无苯型增塑剂、无苯无酮环保型油墨、聚对苯二甲酸乙二酯和聚丙烯等新材料,同时采用活性包装、抗菌包装、用氧化法漂白替代含氯物质漂白等新技术,从根本上提高我国食品包装材料的安全性.     

纸质食品包装材料迁移测试研究用固体食品模拟物的选择

利用气相色谱-质谱联用技术(GC-MS),对市面上常用纸质包装材料进行包装的食品——米粉、大米、脱脂奶粉、白砂糖,以及目前研究常用的、价格昂贵的食品模拟物Porapak的热稳定性与对各种模拟污染物的吸收性能进行了分析,以寻求代替Porapak用于分析纸质食品包装材料迁移测试的最佳食品模拟物。研究结果表明,在100℃时,出现了大米熟化、白砂糖热分解、脱脂奶粉焦化的现象,与其他食品相比,米粉的热稳定性最好;对75℃时各食品(模拟物)对模拟污染物的吸收性能依次为:Porapak米粉脱脂奶粉白砂糖大米,米粉与Porapak的吸收性能最接近,可以利用米粉代替Porapak,作为食品模拟物进行迁移测试实验。     

缓冲包装材料的本构建模研究进展

在多年研究及大量文献调研的基础上,综述了瓦楞纸板、发泡聚乙烯、蜂窝纸板、纸浆模塑、植物秸秆等常用缓冲包装材料的本构模型研究进展,并指出了相关模型的特点与存在的问题。为缓冲包装材料本构建模的进一步研究提供参考。     

利用凤眼莲制作生物质复合包装材料的研究

通过对凤眼莲破碎、热压成型和干燥加工,制备了生物质复合包装材料。 通过分析凤眼莲的纤维特性,并添加胶黏剂等助剂,成功制备了生物质复合包装材料。 研究结果表明,添加胶黏剂等助剂制备的生物质复合包装材料,强度要高于未添加助剂的材料,其助剂适合于生物质复合包装材料的制作。 利用生物质材料的特性,运用精密模压技术加工的生物质复合包装材料,在食品包装、农林牧副产品的包装及运输材料等方面,具有广泛的应用前景,符合绿色化学及可持续发展的战略方针。     

透明食品包装材料防紫外性能的检测与评价

对21种透明食品包装材料进行了透射光谱分析,获得了透射光谱。将紫外线透射比评价模型引入到了透明包装材料防紫外线性能的评价中,并对该评价体系进行了验证。结果表明,该评价体系能直观、可靠地评价透明包装材料防紫外线的性能。     

Polymer-Derived High-Temperature Nonoxide Materials: A Review

This review is focused on an attractive class of polymer-derived high-temperature ceramics, namely, polymer-derived nonoxide materials. With a brief introduction of high-temperature nonoxides, the origin of using polycarbosilane (PCS) polymer melt spinning to synthesize silicon carbide (SiC) fibers is traced back. For SiC formation, the four stages for the conversion from polymer precursors to microcrystalline ceramics are examined first: crosslinking, polymer decomposition, ceramic formation, and crystallization. Also, the important parameters related to PCS pyrolysis are explained, and polymer-derived SiC microstructures and compositions are evaluated. Solid-solution carbides and transition metal carbides are further reviewed. For boride materials, the discussion is focused on transition metal borides and boride composites. Similar to PCS conversion to SiC, nitride materials mostly start with polycarbosilazane (PSZ) precursors and form into the final materials through pyrolysis. With different carbide and nitride precursors mixed and pyrolyzed together, high-temperature nonoxide composites are formed. Such molecular-level intermixing and versatile capability of forming different shapes enable many exciting properties. Among these are mechanical and thermal properties, along with electrical conductivity, electromagnetic shielding, and charge storage capability. An overview of applications of polymer-derived nonoxides is provided, followed by a summary and outlook.     

食品包装—塑料薄膜的阻隔包装设计

为保证食品安全、减少食品质量损失和满足消费者对食品的要求，阐述了食品包装薄膜的阻隔包装设计原理，探计设计程序和设计方法。     

金属类食品接触材料和制品的安全性研究进展与相关法规

金属类食品接触材料及制品对人类健康的影响已引起了广泛的关注。本文介绍了金属类食品接触材料特定迁移物等影响材料安全性的物质,以及在金属类食品接触材料使用和加工过程中产生的不安全因素,综述了德国、意大利、日本、美国等发达国家的法规限制情况以及我国法规现状。     

Nanomaterials: a Map for Their Selection in Food Packaging Applications

Even though research on nanotechnology has increased rapidly in the last decades, the application of nanotechnology in food and beverage packaging started to show an interest in the scientific community much more recently. Food safety, quality and improvements of properties compared with conventional materials make nanomaterials very attractive in the field of food and beverage packaging applications. Furthermore, in many cases, nanomaterials are used for both food packaging and the food contained, especially when we talk about nanomaterials for active and intelligent packaging. Oxygen scavengers, antimicrobial nanomaterials and nanobiosensors are some examples of current research efforts on nanomaterials for food packaging. This fact has led to a variety of nanoparticles and nanomaterials. The wide range of existing nanomaterials could make its selection for food packaging applications a challenge. Thus, building up a map based on the current state‐of‐the‐art nanoparticles and nanomaterials is required. Furthermore, there is a need to classify all the nanomaterials used specifically in food packaging, independently of their nature, the packaging material and the way they are integrated to this material. In this paper, a classification of the latest advances in this field was made accompanied by the use of Multi‐Criteria Decision Analysis in order to find which are the most relevant (and/or expected to be potentially exploited in the near future) nanomaterials in the area of food packaging. Copyright © 2014 John Wiley & Sons, Ltd.     

Equal-channel angular sheet extrusion of interstitial-free (IF) steel: Microstructural evolution and mechanical properties

Interstitial-free steel (IF-steel) sheets were processed at room temperature using a continuous severe plastic deformation (SPD) technique called equal-channel angular sheet extrusion (ECASE). After processing, the microstructural evolution and mechanical properties have been systematically investigated. To be able to directly compare the results with those from the same material processed using discontinuous equal channel angular extrusion, the sheets were ECASE processed up to eight passes. The microstructural investigations revealed that the processed sheets exhibited a dislocation cell and/or subgrain structures with mostly low angle grain boundaries. The grains after processing have relatively high dislocation density and intense micro-shear band formation. The electron backscattering diffraction (EBSD) examination showed that the processed microstructure is not fully homogeneous along the sheet thickness due probably to the corner angle of 120° in the ECASE die. It was also observed that the strengths of the processed sheets increase with the number of ECASE passes, and after eight passes following route-A and route-C, the yield strengths reach 463 MPa and 459 MPa, respectively, which is almost 2.5 times higher than that of the initial material. However, the tensile ductility considerably dropped after the ECASE. The limited ductility was attributed to the early plastic instability in the tensile samples due to the inhomogeneous microstructure. The specimen orientation with respect to the ECASE direction did not have a considerable effect on the stress-strain response. Appropriate low temperature annealing of ECASE-processed IF-steel resulted in a good strength-ductility balance.