PET/TiO2纳米复合材料的吸氧性能研究EI

利用溶液共混法制备了PET/TiO2纳米复合材料并用SEM进行表征,自行设计、加工了用于表征该复合材料吸氧性能的测试系统,并通过实验确定了进行吸氧性能测试的具体实验方法.通过对紫外照射下该体系的吸氧性能测试得到了一定TiO2含量下TiO2与三乙醇胺(TEOA)的最佳配比,并且用红外光谱分析了PET/TiO2体系的吸氧特性.结果表明:PET/TiO2共混体系确实具备吸收氧气的性质;控制PET与TiO2质量比为4:1,TiO2与TEOA质量比5:1时体系吸氧性能最佳,紫外照射8次后平均吸氧量为2.22mL/g.     

PET/TiO2纳米复合材料的吸氧性能研究

利用溶液共混法制备了PET/TiO2纳米复合材料并用SEM进行表征,自行设计、加工了用于表征该复合材料吸氧性能的测试系统,并通过实验确定了进行吸氧性能测试的具体实验方法.通过对紫外照射下该体系的吸氧性能测试得到了一定TiO2含量下TiO2与三乙醇胺(TEOA)的最佳配比,并且用红外光谱分析了PET/TiO2体系的吸氧特性.结果表明:PET/TiO2共混体系确实具备吸收氧气的性质;控制PET与TiO2质量比为4:1,TiO2与TEOA质量比5:1时体系吸氧性能最佳,紫外照射8次后平均吸氧量为2.22mL/g.     

环化SBS吸氧共混物的制备及其性能研究

目的 制备环化SBS吸氧共混物并对其性能进行研究。方法 以苯乙烯-丁二烯共聚物（SBS）为原料, 在对甲苯磺酸的催化作用下, 制备苯乙烯-丁二烯共聚物环化物 （环化SBS）。将环化SBS与引发剂、 过渡金属催化剂共混制备环化SBS吸氧共混物, 经紫外光照射引发吸氧反应从而吸收氧气。研究环化SBS吸氧共混物的吸氧性能, 以及吸氧反应对吸氧共混物结构与性能的影响。结果 吸氧共混物的吸氧量在第4天时就达到30.7 mL/g, 随着时间的延长, 吸氧量继续增加, 在第10天时基本达到平衡,最大吸氧量为40.2 mL/g。环化SBS经紫外光照射引发吸氧后生成醇类物质, 吸氧后环化SBS吸氧共混物的拉伸强度与断裂伸长率均略有降低, 但是变化不显著。结论 试验制备的环化SBS吸氧共混物具有良好的吸氧性能, 可用于制备单层/多层吸氧薄膜。     

PET与PE混合物的回收——原位微纤化方法及其性能研究

研究了原位微纤化方法在回收聚对苯二甲酸乙二醇酯(PET)和高密度聚乙烯(HDPE)混合物方面的应用。本文通过四次挤出模拟塑料制品在环境中遇到的热氧作用和多次回收过程,研究了原位微纤化PET/HDPE共混物以及普通PET/HDPE共混物的性能变化。结果表明,随着挤出次数的增加,PET/HDPE普通共混物的拉伸性能和加工性能均下降,而PET/HDPE原位微纤化共混物的屈服强度得到了较大提高,同时模量也得到一定的提高。     

聚乳酸/聚酯共混体系熔体流变性能研究

对聚酯与聚乳酸共混体系的相容性及熔体流变性能进行了研究。首先制备不同比例的PET/PLA共混体系,并利用示差扫描量热仪(DSC)研究共混体系的相容性,发现m(PLA)/m(PET)在20%以内时相容性较好。而后利用毛细管流变仪研究了不同温度、不同剪切速率下共混体系的熔体流变性能,发现随PLA含量的增大,非牛顿指数先增加后减小,且在m(PLA)/m(PET)=10%时出现极大值;黏流活化能则随PLA含量的增大而降低;另外当m(PLA)/m(PET)=10%时的共混体系可纺性较好。     

具有高界面压应力的高分子共混物Ⅰ.制备和拉伸性能

考察了高界面压应力对不相容聚对苯二甲酸乙二醇酯(PET)/聚乙烯(PE)和聚碳酸酯(PC)/PE共混物拉伸性能的影响.高界面压应力是共混物低温成型(PE的成型温度)时,分散相与基体从加工温度冷却到室温过程中基体的收缩比分散相粒子大产生的.尽管PET/PE和PC/PE共混物极不相容,但拉伸强度和模量随着PET和PC含量增加而增加.PET与PC含量相同时,PC/PE的拉伸强度和模量高于PET/PE的.采用Takayanangi方程计算共混物的拉伸模量时,具有高界面压应力的PC/PE共混物的拉伸强度高于界面有良好粘结的共混物的理论值,表明在不添加增容剂时,可通过控制加工条件改善共混物界面相互作用,提高共混材料的性能.     

成核剂对PET/PEN共混体系热降解与结晶形态的影响

用热失重(TGA)、X射线(WAXS)和偏光显微镜(PLM)研究了三种成核剂对聚对苯二甲酸乙二酯/聚萘二甲酸乙二醇酯(PET/PEN)共混体系的热降解行为、结晶行为和形态的影响。结果表明,成核剂的加入,加速了PET/PEN共混物的降解;且DBS[1,3:2,4-二(亚苄基)-D山梨醇]对PET/PEN共混物的影响最大,CaCO3对PET/PEN共混物的影响最小;含有DBS的PET/PEN共混物形成了环带球晶,CaCO3与PET/PEN共混物同时结晶,且成核剂的加入使晶体形态更完善。用差减微分法研究了PET/PEN/成核剂共混体系热降解动力学,计算得到了活化能(E)和反应级数(n),计算得到的活化能关系为EPET/PEN>EPET/PEN/DBS>EPET/PEN/CaCO3>EPET/PEN/SB。     

环氧类扩链剂的合成及对回收PET的扩链效果

采用悬浮聚合方法合成了环氧类扩链剂苯乙烯-EMC的共聚物SMC,并对其进行红外分析表征。SMC中含有活性环氧基团,可与回收PET链端的羧基反应,将其用于PET(聚对苯二甲酸乙二醇酯)的反应共混,能够大大提高回收PET的分子量,特性黏度从0.448 dL/g提高至0.57 dL/g,羧基含量减少至很低,扩链效果显著。DSC分析扩链后的PET其固有性能保持不变。这种共聚物可作为PET的扩链剂使用。     

增容剂对回收聚对苯二甲酸乙二醇酯/乙烯-辛烯共混物结晶性能的影响

以甲基丙烯酸环氧丙酯接枝乙烯-辛烯共聚物(mPOE)为增容剂对回收聚对苯二甲酸乙二醇酯(r-PET)/乙烯-辛烯共聚物(POE)共混物进行增容改性。用HAAKE流变仪、差示扫描量热仪(DSC)、广角X射线衍射(WAXD)分别研究了不同mPOE含量对r-PET/POE共混物的扭矩变化和接枝共聚物对PET结晶性能的影响。结果表明,共混物的扭矩随着mPOE含量的增加而增大,即mPOE与r-PET生成的接枝共聚物POE-g-PET含量增大。DSC和WAXD结果表明,POE对PET有异相成核作用,而POE-g-PET共聚物对PET结晶有一定的阻碍作用。     

TPU与纳米SiO2共混增韧改性PET研究

采用热塑性弹性体TPU共混增韧改性PET树脂,在共混物中加入成核剂纳米SiO2提高PET的成核性,同时采用硅烷偶联剂KH-560与氨基偶联剂A-1100两种不同的偶联剂对SiO2进行改性,以提高其在树脂中的相容性和分散性。研究了TPU、成核剂的用量及偶联剂的种类与用量对体系力学性能的影响。结果表明:TPU的加入提高了PET的韧性,但强度及刚性有所降低,且30%的添加质量分数较合适;质量为共混物1%的成核剂SiO2可有效提高PET的成核性,从而提高材料的强度,但对断裂伸长率影响不大;氨基硅烷偶联剂A-1100较硅烷偶联剂KH-560有更好的改性效果。     

Quality of orange juice in barrier packaging material

The vitamin C content and the colour of orange juice made from concentrate were measured during 9 months of storage at 20°C either under artificial light or in darkness. The packaging materials used were glass, standard monolayer polyethylene terephthalate (PET) and multilayer PET (PET/nylon and oxygen scavenger/PET) containers. In this experiment, all bottles were sealed with aluminium foil in order to avoid any cap effect. The results showed that in plastic packaging materials, the loss of vitamin C was related to the oxygen permeability, and that glass provided the best preservation of ascorbic acid. No statistical difference (p < 0.05) was revealed between the vitamin C content in the juice stored under artificial light or in darkness, whatever the packaging used. The modification of colour was studied with the L, a* and b* values during storage at 20°C under artificial light. L and b* decreased, revealing a reduction of lightness and yellow colour of the juice, whereas a* increased, due to the formation of brown pigments. This change in colour was partly related to the oxygen permeability of the packaging used. The losses of aroma compounds by permeation through the bottle (PET) and the cap (high‐density polyethylene, HDPE) have also been investigated. The results showed that permeation mainly took place through the cap. The use of a multilayer cap [HDPE with internal barrier layer of low‐density polyethylene (LDPE)/EvOH/LDPE] considerably limited the permeation of the aroma compounds studied, whatever the PET bottle used. Copyright © 2007 John Wiley & Sons, Ltd.     

高阻氧性PET果汁饮料瓶的研究发展趋势

论述了提高PET果汁饮料瓶阻氧性的意义和方法.介绍了不同共混法制取PET果汁饮料瓶的国内外研究现状,指出了提高PET果汁饮料瓶阻氧性研究的方向,有利于PET材料在果汁饮料包装领域的广泛应用.     

Influence of PET bottle weight,closure performance and filling Technique on the oxygen content of soya cooking oil

The use of PET bottles for edible oil in Brazil is increasing but there is a trend to reduce bottle weight for economic reasons, which decreases the oxygen barrier of the package. The barrier performance of a 20 g PET bottle for 900 ml soya oil, submitted to gas flushing with gaseous N₂ and pressurization with liquid N₂, was compared with a 27 g PET conventional bottle. During 8 months storage at 25°C the internal pressure, dissolved oxygen and oxygen in the headspace were evaluated and did not change significantly. Liquid N₂ pressurization did not improve the efficiency of reducing O₂ in the headspace compared to N₂ gas flushing. Copyright © 2001 John Wiley & Sons, Ltd.     

不同包装橙汁贮藏期间物理品质的变化

以纸铝塑复合包装、普通PET瓶和充氮PET瓶包装的橙汁为研究对象,监测其物理指标,如褐变度、可溶性固形物、pH值、表观黏度及流变特性,在不同温度下贮藏24周过程中的动态变化。结果表明,试验周期内不同包装橙汁褐变度的变化符合一级动力学模型;橙汁的流体性质均属于假塑性流体;pH值随贮藏时间延长而降低;可溶性固形物含量在4℃和20℃下无显著变化(P0.05),而在37℃和55℃下呈上升趋势。研究表明,纸铝塑复合包装可以保持橙汁物理品质相对稳定,而从节约成本和携带方便等方面考虑,充氮PET瓶仍是较优的包装方式。     

加工工艺条件对PET/PEN共混瓶性能的影响

对聚对苯二甲酸乙二醇酯/聚2,6-萘二甲酸乙二醇酯(PET/PEN)共混复合瓶坯的成型温度和时间对瓶子表观和微观结构的影响进行了研究。使用扫描电镜、质子核磁共振(1 H-NMR)和透光率测定仪等方法,对PET/PEN共混复合瓶的微观结构、酯交换率和透明度进行了表征。结果表明,在300℃下,PET和PEN共混熔融时间为180s,制得的PET/PEN共混复合瓶具有很好的透明度;并且,其水蒸气透过量较PET瓶降低了19.1%,阻湿性优于食用油常用的PET瓶。     

Quantification of the Sorption Behavior of Polyethylene Terephthalate Polymer versus PET/PA Polymer Blends towards Organic Compounds

Polyethylene terephthalate (PET) bottles are widely used for beverages. Oxygen‐sensitive beverages, however, often require the use of barrier materials or oxygen‐scavenging additives incorporated into the PET material, which is in most cases polyamide (PA). As a consequence, small amounts of polyamide are entering the PET bottle‐to‐bottle recycling feedstream. Aim of the study was therefore the determination of the sorption behavior of bottles made of different PET/PA blends in comparison with a PET reference. As a result, PET test bottles containing blended PA amounts of up to 1000 ppm do not show a sorption behavior for the investigated model compounds, which is different from pure PET material. Therefore, polyamide impurities in the recycling streams coming from polyamide barrier bottles will not lead to a different sorption/remigration behavior as pure PET bottles. Consequently, evaluations of PET recycling processes will still be valid for feedstream materials containing such small amounts of polyamide from barrier bottles. On the other hand, the introduction of 8% of polyamide decreases significantly the sorption of organic compounds into the bottle wall. Copyright © 2011 John Wiley & Sons, Ltd.     

PET 瓶装碳酸饮料货架期影响因素研究

目的研究影响碳酸饮料货架期的各种因素。方法以PET瓶装碳酸饮料为研究对象,分析了PET瓶的二氧化碳泄漏的途径,通过4类实验分析了温度、壁厚、二氧化碳阻隔剂、气含量等因素对其泄漏速度的影响。结果常温下瓶体是二氧化碳泄露的主要途径,降低仓储温度、增加瓶子壁厚,在PET料里添加二氧化碳阻隔剂以及增加气体含量都可以有效延长货架期,而高温下气体含量高的饮料的货架期可能更短。结论实验得到了不同仓储温度、瓶子壁厚、不同初始含气量以及添加二氧化碳阻隔剂与产品货架期的关系。     

Long‐time Performance of Bottles Made of PET Blended with Various Concentrations of Oxygen Scavenger Additive Stored at Different Temperatures

Blending of poly(ethylene terephthalate) (PET) with oxygen scavenger additives is a way to reduce ingress of oxygen into PET bottles made of these blends. The objective is to reduce oxidation of packaged beverages and oils. However, few studies were performed about the long‐time influence of temperature on PET bottles with oxygen scavenger additives. Such knowledge is relevant for the development of accelerated tests. In this study, the influence of temperature on oxygen permeation of PET bottles with the oxygen scavenger additives MXD6 or Oxyclear® was examined. PET bottles made of blends of PET with 2, 5 and 8 wt.?% MXD6, respectively, or with 2 wt.?% Oxyclear® were filled with deoxygenated water. The bottles were stored at 5, 23, 38 and 55 °C up to 5 years. Oxygen partial pressure of the water in the bottles was measured regularly. As expected, oxygen partial pressure increased earlier at higher temperature because of faster exhaustion of the oxygen scavenger. Oxygen partial pressure of water in PET bottles with 8 wt.?% MXD6 was below 10 mbar even after 5 years storage time at 5 and 23 °C. Oxygen absorption capacity of activated MXD6 was at least 76 mg/g. This study shows that PET bottles with oxygen scavengers are able to reduce the oxygen ingress for several years, even at elevated temperatures. Copyright © 2017 John Wiley & Sons, Ltd.     

Comparative effects of de‐aeration and package permeability on ascorbic acid loss in refrigerated orange juice

Several factors including pH, cultivar, extraction method, metal ion content and storage conditions affect the rate of ascorbic acid loss in refrigerated fruit juices. While oxygen permeation rate and product de‐aeration also influence ascorbic acid loss, little comparative data on these two variables exist despite the potential usefulness of such data in optimizing the packaging of juice. De‐aerated and non‐de‐aerated single‐strength orange juices were packaged and stored at 7°C in experimental glass containers constructed with oxygen permeability rates of 0·35, 0·39, 0·43, 0·79, 1·18 and 1·60 ml/day/container at 7°C. The rate of ascorbic acid degradation inversely correlated with permeation rate for both de‐aerated and non‐de‐aerated juices regardless of initial dissolved oxygen content. Degradation was best described by zero‐order and first‐order kinetics for de‐aerated and non‐de‐aerated juices, respectively. Headspace volume had no effect on ascorbic acid loss in both de‐aerated and non‐de‐aerated juices when nitrogen flushed. Juice in high oxygen permeability containers showed a faster decrease in ascorbic acid content, independent of initial dissolved oxygen content. These results indicate that both package barrier properties and de‐aeration are major factors in maintaining ascorbic acid in refrigerated orange juice. Copyright © 1999 John Wiley & Sons, Ltd.     

四种低温储藏条件对橙汁品质的影响研究

研究了巴杀橙汁在较高温冷藏环境(8℃)、较低温冷藏环境(4℃)、冰温(-2℃)以及冻藏(-20℃)四种不同温度下储藏五周的品质变化规律。结果表明:与其他储藏温度相比,冰温条件下储藏的橙汁在可溶性物、挥发性风味物质等与风味相关的指标上更具优势,也就是该条件下储藏的橙汁的风味品质更优。在维生素C的保存方面,冻藏则更具优势。8℃储藏条件下的橙汁在品质上劣于其他三种储藏温度。1)冰温条件下,储藏期间橙汁的可溶性固形物变化最小;检测出的挥发性风味物质种类最多,其中萜烯类、醇类种类最多,醇类和酯类的相对含量最高。2)冻藏条件下,第五周时VC含量最高;检测出的挥发性风味物质中,醛类的相对含量也最高。3)冷藏条件下,较高储藏温度的果汁的可溶性固形物含量变幅较大;检测出的挥发性风味物质中,化合物总数最少,但烯萜类组分的相对含量最高,重要风味贡献物月桂烯、里那醇和柠檬醛的相对含量最低。4)各储藏条件下,橙汁的总酸、pH值和色度的变化差异不显著。