PET包装薄膜渗透性能的影响因素分析

研究了温度、相对湿度、薄膜厚度对聚对苯二甲酸乙二醇酯（PET）包装薄膜的渗透性能的影响规律，分析了PET包装薄膜对氧气（O2）、二氧化碳（CO2）气体的选择透过性，基于气体分子渗透反应动力学和回归分析法获得了渗透率的经验公式。结果表明，PET薄膜、PET镀铝（PET/Al）薄膜对水蒸气（H2O）、O2、CO2的渗透性能（透湿率、透气率）随着温度的升高而增加，渗透率（透气率、透湿率）的对数形式与热力学温度的倒数呈线性关系；相对湿度对12 ?m PET薄膜透湿率的影响最小，而对20 ?m PET薄膜、18 ?m PET/Al薄膜的影响稍明显；PET薄膜对O2、CO2气体具有显著的选择透过性，CO2透气率是O2透气率的约2倍，而PET/Al薄膜对O2、CO2气体的透气率都很低且差异甚小，具有优异的阻透性能。     

阻隔性薄膜透气性能的压差法和等压法测试分析

利用压差法、等圧法研究了4种阻隔性塑料薄膜的氧气和二氧化碳气体透过量,分析了温度、薄膜类型和厚度、相对湿度对透气性能的影响关系,对比了2种测试方法的薄膜透氧量。结果表明,12 μmPET、12 μmPET/Al、25 μmPET和25 μmPVDC薄膜的氧气、二氧化碳气体的透过量都受温度影响显著,都随着温度的升高而增大,其对数形式与热力学温度的倒数都呈线性关系;这4种阻隔性薄膜对氧气、二氧化碳气体的透过性能都存在明显差异,12 μmPET薄膜的透过量最大,25 μmPET薄膜和25 μmPVDC薄膜次之,12 μmPET/Al薄膜最小,而且它们对二氧化碳和氧气的透过量之比值都超过了4倍,都具有优良的阻隔性能和选择透过性。     

PET/CNFs复合膜的制备及其阻透性能

将聚对苯二甲酸乙二酯(PET)与纳米碳纤维(CNFs)进行预处理,采用溶液法制备PET/CNFs复合乳液,涂覆于聚四氟乙烯板上风干,得到PET/CNFs复合膜,研究了该复合膜的阻透性能。结果表明:随着CNFs含量的增加,PET/CNFs复合膜在同一湿度下的氧气透过率略有增大,加入CNFs改善了PET薄膜的水蒸气阻透性能,提升了PET薄膜的耐紫外光透过能力;在保持湿度不变的情况下,环境温度越高,二氧化碳透过率越大,且复合膜的厚度对二氧化碳透过率影响较大;加入CNFs对复合膜的阻油性起反作用,复合膜的透油率大幅增加。     

不同材质复合膜耐揉搓性比较与分析

选取了塑料包装中常用的5种材质,分别为聚酯(PET)/铝(Al)/尼龙(PA)/聚乙烯(PE)、PET/Al/PE、PET/聚酯镀铝(VMPET)/PE、 PET/PE、PA/PE的塑料复合膜薄膜,并对上述薄膜进行20 min,900次的揉搓,检测揉搓前后氧气透过量、拉断力、断裂伸长率、抗摆锤冲击能的数据变化。结果表明:揉搓对薄膜的4项性能均有不同程度影响,对氧气透过量影响较大,对抗摆锤冲击能影响较小;5种材质中,PET/Al/PE揉搓后性能变化较大,PET/PE和PA/PE性能变化较小。     

建筑外墙涂料水蒸气透过性能测试方法比较

涂料的透湿性直接影响了外墙保温系统保温效果的发挥,其良好的透湿性对于现代建筑节能意义重大.但当前市场中外墙涂料的透湿性能参差不齐,对此国家和建筑行业制定了详细的测试方法供涂料生产企业和使用方进行性能验证.通过对比GB/T 17146-1997《建筑材料水蒸气透过性能试验方法》和JG/T309-2011《外墙涂料水蒸气透过率的测定及分级》关于试验方法的异同,并以市售乳胶漆为例详细介绍了JG/T 309中关于水蒸气透过率的测试方法,证明了减重法涂料水蒸气透过率测试具有一定的合理性和操作性.     

聚偏二氯乙烯保鲜膜的开发与应用

一、概述 聚偏二氯乙烯(PVDC)是氯乙烯(VC)和偏二氯乙烯(VDC)的共聚物,一般采用乳液法聚合工艺生产。以合适比例聚合的树脂再进行挤压、吹膜可以得到优异的保鲜包装材料。PVDC薄膜的首要特性是优良的阻隔性能,即很低的透氧率和透湿率     

PCL对PBAT薄膜气体透过率的影响

采用双螺杆挤出流延拉伸机组制备了聚己二酸-对苯二甲酸丁二酯/聚己内酯(PBAT/PCL)共混薄膜,并分别在不同环境温度和湿度下,研究了PBAT/PCL共混薄膜的气体透过率。结果表明:随着PCL用量的增加,PBAT/PCL共混薄膜出现较为明显的相分离,且晶体间的结晶会提高材料的阻隔性;PBAT/PCL共混薄膜的透氧系数最多降低了104%,透湿系数最多降低了38%;对于同一厚度的共混薄膜,随着温度和湿度的提高,其气体透过率增大。适宜用量的PCL可以提高共混薄膜晶体间的结晶度,降低其气体透过率,并且温度和湿度与气体透过率呈正相关。     

不同粒径碳酸钙对PBAT复合薄膜性能的影响

用硬脂酸对三种不同粒径的碳酸钙（CaCO₃）进行表面改性,并通过傅里叶变换红外光谱分析证实了硬脂酸已成功包覆在CaCO₃表面上。采用熔融共混吹膜法制备聚己二酸/对苯二甲酸丁二酯（PBAT）/改性CaCO₃复合薄膜,研究不同粒径的改性CaCO₃对复合薄膜熔融结晶行为、力学性能和水蒸气透过性能的影响。结果表明,加入改性CaCO₃后,PBAT的结晶温度、结晶度及熔融温度都有所提高,当加入体积平均粒径为7.6 μm的改性活性CaCO₃时,结晶温度和结晶度均达到最大值。加入改性CaCO₃后,PBAT/改性CaCO₃复合薄膜的力学性能均有明显的提高,且随着改性CaCO₃粒径减小,力学性能逐渐升高。当添加体积平均粒径为0.34 μm的改性纳米CaCO₃时,复合薄膜的拉伸强度达到了最大值19.9 MPa,比纯PBAT增加了10.07 MPa,断裂标称应变达到了551.8%,较纯PBAT...     

光伏组件背板用高反射率PET薄膜性能

通过双向拉伸制孔技术制备高反射率聚对苯二甲酸乙二酯(PET)薄膜,采用高压加速湿热老化(PCT)试验评价老化性能,使用紫外/可见光/近红外分光光度计、扫描电子显微镜(SEM)、拉力试验机、差示扫描量热仪分别表征了PET薄膜PCT 48 h前后的反射率、断面形貌、拉伸强度和断裂伸长率、结晶度。使用击穿电压测试仪测试了PCT 48 h前PET薄膜的击穿电压(油)。结果表明,相比于半透型PET薄膜,由于微米级孔的产生使得高反射率PET薄膜的反射率(420～1-200 nm)从34.8%提高到95.9%,密度从1.4 g/cm~3降到1.2 g/cm~3,微米级孔的直径为3～8 μm,高度为0.2～0.8 μm,击穿电压(油)从16.0 kV提高到26.0 kV。经过PCT 48 h处理后,高反射率PET薄膜的微米级孔结构和反射率没有明显变化,拉伸强度和断裂伸长率保持率在50%以上,结晶度从27.8%提高到30.5%。     

一种PVDC复合膜的研究及其在牙膏包装中的应用

实验以黏合的方法制备了聚乙烯(PE)/聚偏二氯乙烯(PVDC)/低密度聚乙烯(LDPE)复合膜并将其运用在了牙膏包装领域,对其透湿度、氧气透过率、光泽度以及力学性能进行了研究。实验中将PVDC、PE、聚氯乙烯(PVC)分别作为中间层材料,采用胶黏剂,将印刷聚乙烯薄膜、中间层材料、白色聚乙烯薄膜依次黏合,并对其各项性能进行测试。研究表明,由胶黏剂将印刷PE薄膜、PVDC薄膜和LDPE薄膜依次黏合而成的薄膜具有最优的阻隔性和力学性能。研究所制得的包装材料具有无害的特性,在牙膏等包装领域中具有广阔的应用前景。     

Morphology,order, light transmittance,and water vapor permeability of aluminum‐coated polypropylene zeolite composite films

In this study, the polypropylene–zeolite composite films having 2–6 wt % natural zeolite were coated with a thin film of aluminum (Al) by magnetron sputtering, and the contribution of the Al coating on film properties was investigated. The samples were characterized by EDX, X‐ray diffraction, SEM, AFM, UV–visible spectroscopy, and water vapor permeation analyses. The surface of the films coated with a smooth Al film having 98–131 nm thickness. EDX revealed that Al percentage on the surface appeared to be as 8–10 wt % indicating contribution of polymer surface under Al film to analysis. XRD analysis showed that the grain size of Al at the surface was 22–29 nm. The surface roughness increased after Al‐coating process. The transmission of coated films was very low for both UV and visible regions of the light spectrum. Permeation analysis indicated that water vapor permeation was lower for Al‐coated material. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Adhesion of UV-Cured Laminates of Poly(ethylene-2,6-naphthalate) (PEN) and Poly(ethylene terephthalate) (PET) films

This paper describes the properties of an ultraviolet (UV) curable laminating adhesive system that can be used with PEN, PET and UV-stabilized PET films. The adhesive system that contains (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) as photoinitiator was optimally cured with a V-bulb fitted ultraviolet irradiator. The laminated structures built with this adhesive system and PEN, PET and UV-stabilized PET films showed a large manufacturing operating window, both in terms of adhesive layer thickness, initial peel strengths above 1500 N/m, V- and D-bulb UV sources and curing speeds from 5– 10 m/min. The 600-h dry heat aging tests indicated that the UV-stabilized PET films underwent less than approximately 1% decrease in light transmission and less than a 1% gain in color. The UV-stabilized PET film and its laminate showed particularly strong retention of optical properties under damp aging and QUV weathering, compared to PEN and non-UV-stabilized PET films. Finally, the peel strengths of the laminates were retained to greater than 1300 N/m for laminate structures of 50 μm film thickness, whereas structures made from thicker films retained approx. 40–60% (700–1100 N/m) of their initial peel strength.     

Mechanical properties and water vapor permeability of thin film from corn hull arabinoxylan

Isolated corn hull arabinoxylan was dissolved in water and provided a clear solution. Plasticizer (glycerol, propylene glycol, or sorbitol) was added to the arabinoxylan solution at 0–20 wt % (film dry weight), which was cast into stable films. Film thickness ranged from 22 to 32 μm. Mechanical properties, moisture content, and water vapor permeability (WVP) were studied for the arabinoxylan‐based films as a function of plasticizer concentration. Measured data for the corn hull arabinoxylan–based films were 13–18 wt % moisture content, 10–61 MPa tensile strength, 365–1320 MPa modulus, 6–12% elongation, and 0.23–0.43 × 10^?10 g m^?1 Pa^?1 s^?1 water vapor permeability. Plasticized arabinoxylan films produced in this study had lower WVPs than those of unplasticized films, which is likely attributable to the phenomenon known as antiplasticization. Scanning electron micrographs showed a homogeneous structure on film surfaces. Films containing sorbitol had the best moisture barrier properties. When grapes were coated with arabinoxylan and arabinoxylan/sorbitol films, weight loss rates of the fruit decreased by 18 and 41%, respectively, after 7 days. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2896–2902, 2004     

Vapor and water permeabilities and moisture absorbability of organosilicate coatings

A setup was designed for determining the vapor and water permeabilities of coatings and films on porous metal substrates at temperatures of 40°C and higher. The setup was used to determine the vapor and water permeabilities of five organosilicate coatings, namely, OS-51-03 (green), OS-51-03A (green), OS-11-07 (green), OS-11-07A (green), and OS-12-03 (white). The thickness of the coatings was in the range 90–130 μm. The water permeability of all the coatings under investigation was found to be higher than their vapor permeability. The lowest vapor and water permeabilities were observed for the OS-51-03 coating (the vapor permeability was 2.76 × 10^?5 mg/m h Pa). The moisture absorption of the green coatings, the OS-12-03 white composite, and the varnish coatings based on the KO-921 varnish and a mixture of the KO-915 and KO-075 varnishes were investigated. No correlation between the moisture absorption and the water permeability was revealed. It was established that the KO-921 varnish coating possesses the lowest water absorbability (0.85%).     

Measurement of water vapor transmission rate in highly permeable films

Measurements of water vapor transmission rate (WVTR) are often based on the wet cup method described by ASTM E 96‐95. In attempting to compare the performance of thin polymer films with moderate to high water vapor permeability, it was observed experimentally that the ASTM method did not give reliable results for highly permeable films. In particular, the WVTR depended on film thickness and the ratio of film area to water surface area. It was determined that the high water vapor flux through the more permeable films caused a reduction in the driving force for water vapor transmission, that is, the relative humidity at the inner surface of the film. Consequently, the WVTR was underestimated. Comparisons based on a small area ratio and a constant small‐flux condition were considered as alternative approaches for evaluating performance using the wet cup method. The constant flux approach produced the best correlation with WVTR that was measured with a commercial instrument. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1624–1633, 2001     

Gas barrier and wetting properties of whey protein isolate‐based emulsion films

The aim of this research was to investigate the effect of rapeseed oil concentration (1–3% w/w) on the water vapor, oxygen and carbon dioxide permeability, water vapor sorption and surface properties of whey protein isolate emulsion‐based films. The water contact angle as affected by oil content, film side and time was analyzed. The effect of temperature (5 and 25°C) on the water vapor permeability (WVP), water vapor sorption kinetics and diffusion coefficient was also studied. The results showed that the incorporation of a lipid phase to whey protein film‐forming solutions was able to decrease the WVP, water hydrophilicity (increasing water contact angle) and water transfer of whey protein films. However, the films containing oil were more permeable to oxygen and carbon dioxide. Significantly higher values of WVP and diffusion coefficient were obtained at 5°C than at 25°C, indicating that storage temperature should be taken into account when designing the composition of edible films and coatings for food applications. POLYM. ENG. SCI., 59:E375–E383, 2019. © 2018 Society of Plastics Engineers     

Hydrophobicity and Water Vapor Permeability of Ethylene-plasma-coated Whey,Chitosan and Starch Films

Abstract

Water vapor transmission rate was measured on uncoated and ethyfeae-plasma-coated whey (65-93.5% whey protein), on chitosan and starch films and on aluminum-coated chitosan. Surface hydrophobicity was assessed by contact angle measurements, and X-ray photoelectron spectroscopy was used to characterize the coatings. The water vapor transmission rate through the uncoated polymer films was highest for starch and lowest for chitosan. Whey showed intermediate water permeability, with the sample containing 65% whey-protein having the lowest water vapor transmission rate. An improvement in water vapor barrier properties was observed only for the aluminum-coated sample and not for any of the polyethylene-coated samples. It is observed that the penetrating water caused the substrate to swell and the polyethylene coating layer to crack. According to profilometry, the thickness of the polyethylene coating layer was 0.1-1 μm after 15 min exposure time. The coating was hydrophobic and contained almost exclusively carbons typical of linear or crosslinked hydrocarbons. It is suggested that the observed decrease in hydrophobicity with time during the contact angle measurements is due to the reorientation at the surface of carbonyls present in small amounts in the coating.     

PVDC薄膜的阻隔性与加工技术

PVDC吹塑薄膜、层合膜和共挤出流延薄膜是高阻隔性的包装材料。PVDC树脂加工过程中易分解和它的结晶特性使它需采用特殊的加工设备和工艺。通过对薄膜生产过程的分步模拟,其结果解释了工艺中冷水槽、温水槽、拉伸比、室温存放中的有关结晶现象,有助于认识加工过程,指导PVDC产品的加工工艺及提高产品性能。