壳聚糖/蜂蜡改善纸基材料水蒸气和氧气阻隔性能研究

围绕壳聚糖(CS)和蜂蜡(Wax)在改善纸基材料气体(水蒸气和氧气)阻隔性能方面开展研究,探讨了蜂蜡添加量及其与壳聚糖的复合方式(共混和分层)对纸基材料阻隔性能和涂层热稳定性能的影响。结果表明,涂布纸的水蒸气透过量随蜂蜡添加量的增加而降低,当蜂蜡添加量为15%时,在50%RH (相对湿度)条件下,分层涂布纸和共混涂布纸的水蒸气透过量分别降至21.87和24.13 g/(m²·d),与纯壳聚糖涂布纸相比,分别降低了80.3%和78.2%,分层涂布纸与共混涂布纸的水蒸气透过量差异不大;在75%RH条件下,分层涂布纸(163.69 g/(m²·d))和共混涂布纸(242.24 g/(m²·d))的水蒸气透过量与纯壳聚糖涂布纸相比,分别降低了79.4%和69.5%,而与共混涂布纸相比,分层涂布纸的水蒸气透过量降低了32%。共混涂布纸和分层涂布纸的氧气透过量随着蜂蜡添加量的增加而增大,当蜂蜡添加量为15%时,分层涂布纸和共混涂布纸的氧气透过量仍低至70.19和101.75 cm³/(m²...     

环保型PLA/CNF应用于纸张阻隔性涂布的研究

以聚乳酸（PLA）为基体、乙酰化改性纤维素纳米纤丝（m-CNF）为增强材料制得复合涂料,将其涂覆于A4纸表面制得PLA/m-CNF阻隔纸,探讨了复合涂料中m-CNF添加量对纸张阻隔性能、疏水性能、强度性能等的影响。结果表明,与原纸相比,当m-CNF添加量为3%时,PLA/m-CNF3%阻隔纸的抗张指数、耐破指数、疏水性能分别提高了30.6%、40.1%、24.8%,透气度降低了36.6%。原纸水蒸气透过量为1815 g/（m²·d）,PLA/CNF阻隔纸的氧气和水蒸气阻隔性能相较原纸显著提升;其中,PLA/CNF3%阻隔纸的水蒸气透过量为443 g/（m²·d）、氧气透过量为45 cm³/（m²·d·（0.1 MPa））;PLA/m-CNF3%阻隔纸的水蒸气透过量为385 g/（m²·d）、氧气透过量为35 cm³/（m²·d·（0.1 MPa））,与PLA/CNF3%阻隔纸相比,分别下降了13.1%和22.2%;表明PLA/m-CNF阻隔纸具有优异的保鲜效果。     

纳米纤维素材料氧气与水蒸气阻隔性能的研究现状

纳米纤维素主要来源于植物纤维，具有比表面积高、强度高、密度低、透明性高、热膨胀低等特点，其特有的形态结构和表面性能使得纳米纤维素材料可以形成致密的网络结构进而提供优良的阻隔性能。本综述就纯纳米纤维素膜、纳米纤维素复合材料以及纳米纤维素涂布纸基材料重点讨论了纳米纤维素材料氧气与水蒸气阻隔性能的研究现状，以探讨纳米纤维素应用于包装材料的可能性。     

壳聚糖添加量对大豆分离蛋白复合包装材料性能的影响

研究壳聚糖添加量对大豆分离蛋白复合材料机械性能、阻隔性能、颜色和结构的影响,以提高大豆分离蛋白可食性包装材料的性能。结果表明:当壳聚糖与大豆分离蛋白的质量比为1∶1时,复合材料的综合性能最佳,其抗拉强度提高,断裂伸展率、水蒸气透过率和氧气透过率降低,颜色略微发黄。红外光谱分析结果显示提高复合材料的机械性能和阻隔能力的主要原因可能是大豆分离蛋白与壳聚糖之间形成醚键或C-N键。     

多糖聚合物涂层对纸基包装材料水蒸气阻隔性能的研究进展

纸基包装材料在一定湿度环境中具有较高的水蒸气渗透性,这极大地限制了其在食品包装领域的广泛应用。多糖聚合物涂层的纸基包装材料充分利用多糖聚合物良好的成膜性能和生物相容性及木质纤维材料优异的强度性能,在水蒸气高阻隔材料领域具有一定的应用潜力。本文介绍了4种常用多糖聚合物（纤维素、淀粉、壳聚糖和海藻酸盐）的理化性质,从传质小分子性质（极性和非极性）考虑,分析了多糖聚合物本身的结构特点及其在水蒸气阻隔方面存在的问题;重点探讨了通过化学改性（酯化、醚化、接枝和交联等）和使用有机/无机纳米填料（纤维素纳米晶、纳米黏土和纳米金属氧化物等）提高多糖聚合物涂层水蒸气阻隔性能的研究进展;最后,提出了多糖聚合物涂层纸基包装材料的未来研究方向及发展趋势。     

涂布抑菌防霉包装纸及其性能研究

将山梨酸钾、脱氢乙酸钠、苯甲酸钠分别溶于聚乙烯醇溶液制得抗菌液,再将抗菌液涂布于牛皮纸上制备得到包装用抑菌纸。采用抑菌圈法检验该抑菌纸对大肠杆菌和金黄色葡萄球菌的抑制效果,研究了涂布抗菌液后对抑菌纸的抗拉强度、撕裂强度、水蒸气透过系数、氧气透过量和微观结构的影响。结果表明,抑菌纸的抗拉强度、撕裂强度、水蒸气透过系数、氧气透过量均有改善,微观结构更加致密均匀,且具有良好的抑菌性能,抑菌效果随抗菌剂浓度的增加而提高,可用于食品的包装。     

壳聚糖应用于纸张阻隔性涂布的研究

使用壳聚糖溶液对纸张进行涂布,研究了不同涂布量下纸张表面孔隙的封闭程度及涂布纸的阻氧性能与阻湿性能,探讨了壳聚糖/PVDC(聚偏二氯乙烯)复合涂布对涂布纸阻湿性能的改善情况.结果表明,涂布0.46g/m2壳聚糖能够将纸张表面原有孔隙填满,进一步增大壳聚糖涂布量,纸张表面完全被壳聚糖膜层覆盖,平整程度提高.壳聚糖涂布能够显著提高纸张的阻氧性能,当壳聚糖单层涂布量为1.96 g/m2时,涂布纸的氧气透过率相对原纸至少下降了99.3％,但水蒸气透过率相对原纸有所上升.使用壳聚糖/PVDC复合涂布时,在1.96g/m2壳聚糖涂层基础上二次涂布7 40 g/m2 PVDC,水蒸气透过率相对单独涂布壳聚糖下降了66.3％,降至原纸的44.8％,与此同时.阻氧性能及表面抗水性均有较大提升.     

添加单宁对明胶可食膜性质的影响

如何提高明胶膜的机械性能和阻隔性能,一直以来是可食膜研究领域的重要内容。本文以不同剂量(0 mg/g、10 mg/g、20 mg/g、30 mg/g和40 mg/g)单宁添加于明胶液并以浇注法成膜,然后对膜的理化性质进行分析。研究结果发现单宁有效提高了明胶膜的拉伸强度,但降低了其断裂伸长率;当单宁添加量为30 mg/g(明胶干基)时,其拉伸强度最大(22.10 MPa),断裂延伸率最小(40.12%)。与对照膜相比,单宁的添加降低了复合膜水溶性,水蒸气透过率和氧气透过率。在单宁含量添加范围内,水蒸气透过性最低为1.49×10-11 g/(Pa·s·m);水溶性最低为27.76%,氧气透过率最低为21.63 meg/kg。同时,DSC分析表明单宁提高了明胶膜的热稳定性。FT-IR图谱表明单宁与明胶之间发生了以氢键和疏水键为主的物理交联作用。所以,单宁-明胶复合膜在食品包装方面具有潜在的开发价值。     

纳米高阻隔SiOx薄膜的等离子体制备

我国的阻隔包装薄膜采用多层共挤复合薄膜来达到对包装物基本的阻隔性能要求.为了达到包装材料更高的阻隔性,简化工艺并降低生产成本,采用潘宁放电等离子体增强化学气相沉积技术(PDPs),以六甲基二硅氧烷(HMDSO)为单体、氧气为反应气体沉积氧化硅薄膜.研究了不同放电参数,如气体的工作压强、放电功率、沉积时间和氧气和单体的比例等,对二氧化硅薄膜的阻隔性能影响.采用傅立叶红外光谱仪(FTIR)和透湿、透氧测试仪分析了沉积膜的化学结构成分、测试薄膜的阻隔性能,得出如下结论:沉积的薄膜主要成分为氧化硅,透氧率和透湿率分别从135cc/m2/day,24.5g/m2·24h降至约1.7cc/m2/day,1.5g/m2·24h,达到国外先进水平.     

纸基材料水蒸气阻隔性能的研究现状及发展趋势

本课题从纸基材料（PBM）的多层级结构和物化改性方法的角度,系统阐述了PBM水蒸气阻隔性能的研究现状及发展趋势。首先,分析了水蒸气阻隔的特殊性及在PBM不同层级结构上的传输机制;其次,论述了PBM的3D网络内部结构修饰处理对水蒸气阻隔性能影响的研究进展;再次,基于PBM界面结构的改性研究,对比分析了各类阻隔性涂层对水蒸气阻隔性能的影响;最后重点总结了超疏水PBM的研究现状,分析了超疏水性能和水蒸气阻隔性能之间的协同对立关系,探讨了改善超疏水PBM水蒸气阻隔性能的必要性,并为超疏水PBM实现实际应用提出了研发思路和方向。     

纳米微纤丝纤维素及其在造纸中的应用研究现状

本文结合纳米材料定义,简述纳米微纤丝纤维素与传统意义纳米纤维素的共性与区别,在此基础上介绍此类纳米纤维素的制备方法及现阶段存在的主要问题。同时介绍了纳米微纤丝纤维素在造纸中潜在的应用方式,分析其对造纸规模化生产及纸张性能的影响并浅谈其发展面临的机遇与挑战。     

可降解阻隔涂层在纸基食品包装材料中的应用

本文综述了可降解阻隔涂层在纸基食品包装材料中的应用,系统地介绍了涂层的阻隔机理和涂料流变性,基底材料特性对涂层结构和材料阻隔性能的影响;并对纳米纤维素、聚乙烯醇（PVA）、聚羟基丁酸酯（PHB）、聚乳酸（PLA）、淀粉5种常见的可降解聚合物涂层材料的突出优势、不足之处和改性方法进行了对比和总结,对其应用价值进行了展望。     

Different Kinds of Microfibrillated Cellulose as Coating Layers Providing Fiber-based Barrier Properties

In this study,we investigated the barrier properties of different kinds of microfibrillated cellulose(MFC)coating layers.The air,oxygen,and water vapor permeability,as well as the water contact angles(WCA),were measured to quantify the barrier efficacy of the applied coatings.The WCA data showed that the surfaces of MFC-coated cardboards are more hydrophilic than those of uncoated cardboards.However,different MFC coatings realize different oxygen transmission rates(OTRs)and water vapor transmission rates(WVTRs).The MFC coating derived from bleached bamboo pulp subjected to carboxyethylation pretreatment(MFCCBP)gave the best oxygen and water vapor barrier performances.The OTR of the virgin cardboard(>16500 cm³/(m²·24 h))decreased to 4638 cm³/(m²·24 h)after coating with the MFCCBP.The WVTR similarly decreased from 1016.7 g/(m²·24 h)to 603.2 g/(m²·24 h).     

Plasticizer Effect on Grease Barrier and Color Properties of Whey-protein Coatings on Paperboard

Whey protein concentrates with ?80% protein (WPC‐80) plasticized with 0.64 M glycerol or sucrose, or with 0.34 or 0.64 M sorbitol or polyethylene glycol (PEG) 200, produced flexible films. WPC‐80 with hydrolyzed lactose required addition of less sucrose to produce flexible films. WPC‐80 films formed as coatings on paperboard gave a grease barrier comparable to WPI film‐coatings. Long‐term ambient storage of WPC‐80 coated paperboard indicated that the use of sucrose as plasticizer imparted good grease resistance and minimized plasticizer migration.     

水性丙烯酸酯涂料对镀铝原纸阻隔性能的影响研究

将水性丙烯酸酯涂料与传统镀铝原纸涂料面涂后对镀铝原纸性能的影响进行对比分析,结果表明,使用水性丙烯酸酯涂料替代传统镀铝原纸涂料时,镀铝原纸平滑度最高由2243 s提高至12436 s,提高4.54倍;对水阻隔能力由45.8%～73.3%提高至97.9%～99.4%;对乙醇阻隔能力由98.1%～99.1%降低至95.3%～97.4%。     

Properties of Poly(lactide)-Coated Paperboard for the Use of 1-Way Paper Cup

ABSTRACT:  Poly(lactide)-coated paperboards were prepared by a solution coating method, and the effect of coating to improve properties of paperboard used for the manufacturing of 1-way paper cups was tested. Surface of PLA-coated paperboards was smooth and shiny like PE-coated paperboard, and the coating weight and thickness increased linearly with increasing PLA concentration of coating solution. Tensile strength (TS) and elongation at break (E) of the paperboard also increased after PLA coating. Water vapor barrier or water-resistant properties tested, such as water vapor permeability (WVP), water absorptiveness (WA), and contact angle (CA) of water drop, indicated that water resistance of the paperboard was improved through surface coating with PLA. The increase in water resistance of PLA-coated paperboards was mainly due to the hydrophobicity of PLA and the improvement of water barrier properties increased depending on the PLA concentration. In addition, PLA-coated paperboard showed strong heat sealing property when coated with more than 1 w/v% of PLA. Wet strength of PLA-coated (3, w/v%) paperboard was comparable to or greater than that of PE-coated paperboard. All the test results indicated that the PLA-coated paperboard can be exploited for the manufacturing of 1-way paper cups as an alternative to the PE-coated paperboard.     

Oxygen Barrier Properties of Whey Protein Isolate Coatings on Polypropylene Films

Oxygen permeation characteristics of whey protein isolate (WPI) coatings on polypropylene (PP) films were investigated to examine the feasibility of WPI coating as a novel biopolymer oxygen barrier for food packaging applications. Heat‐denatured aqueous solutions of WPI with several plasticizers including glycerol, sorbitol, sucrose, propylene glycol, and polyethylene glycol were applied on the surfaces of PP films previously treated with corona discharge. Among plasticizers used, sucrose conferred the best oxygen barrier property to the WPI‐coated films. Oxygen permeability (OP) of the resulting WPI‐coated films increased significantly with temperature, showing very good agreement with the Arrhenius model. OP of the coated films also increased exponentially with relative humidity.     

Eco-friendly PVA/Kaolin Clay Coating for Barrier Paper

The resistance of wood-fiber paper to water, grease, and water vapor is usually attained by immersing the base paper in hydrophobic oil, laminating with a plastic or metal film, or the application of a barrier coating. Oil impregnation and the addition of films may make the paper difficult to recycle or persistent in the environment owing to their strong binding force and nondegradability. Environmental concerns have attracted worldwide attention to eco-friendly barrier coatings. In this study, degradable polyvinyl alcohol(PVA) and kaolin clay pigment were used to prepare coatings that were applied to a base paper. By measuring the barrier properties of the coated paper, including the water absorptiveness(Cobb60 value), Hercules sizing degree, oil resistance(Kit rating), and water vapor transmission rate(WVTR), an optimal coating formulation and process were proposed. To examine the barrier mechanism of the PVA/kaolin clay coating, we characterized the coating microstructures using a scanning electron microscopy(SEM) and a mercury porosimeter. The results showed that the Cobb60 value and water vapor transmission rate of the coated paper decreased by 61.4% and 98.6%, respectively, compared with the base paper, for a pre-coating weight of 0.98 g/m~2 and a top-coating weight of about 3.23 g/m~2. Furthermore, the Hercules sizing degree rose by a factor of 337.2, while the oil resistance(Kit rating) increased from 0 to 12. The optimum drying temperature for a wet coating layer was found to be 170℃, and the optimum weight ratio of PVA to kaolin clay in the coating was determined to be 50∶50. It was assumed that the PVA/kaolin clay coating improved the smoothness of the paper considerably and decreased the pore size by filling the pores on the paper surface and forming an even film, thus enhancing the paper barrier performance. The coated paper also exhibited good repulpability.