高含量PLA薄膜的制备及性能研究

以Joncryl ADR-4370F(ADR)为增容剂,超细滑石粉(Talc)为成核剂,聚乳酸(PLA)/聚对苯二甲酸-己二酸-丁二醇酯(PBAT)通过熔融共混,然后挤出吹膜。对PLA/PBAT薄膜的热性能、结晶行为、撕裂断面形态、力学性能和阻隔性能进行了研究。结果表明,PBAT的加入改善了PLA的柔韧性。随着PBAT含量(40%~70%)的增加,薄膜的拉伸强度和模量降低,断裂伸长率大幅增加了。薄膜的氧和水蒸气阻隔性能受PBAT影响不大。ADR的加入使得薄膜材料的相容性得到了提高。     

生物可降解聚乳酸/Ecoflex共混薄膜拉伸性能研究

对3种不同的聚乳酸/Ecoflex共混薄膜横向、纵向拉伸强度和断裂伸长率进行了对比分析,并研究了薄膜拉伸性能的影响因素。实验结果表明:聚乳酸(PLA)与Ecoflex的相容性越好,薄膜拉伸性能越好;薄膜纵向拉伸强度和断裂伸长率大于横向拉伸强度和断裂伸长率;加载速率对薄膜拉伸强度和断裂伸长率没有显著影响。     

纳米MgO增强聚乳酸薄膜在食品包装领域的应用

采用溶液流延工艺制备了纳米MgO增强聚乳酸(PLA)薄膜。研究了纳米MgO质量分数分别为0.5%,2.0%,3.5%,6.0%的PLA/MgO薄膜的力学性能、阻隔性能、热性能等。结果表明:与PLA薄膜相比,纳米MgO质量分数为2.0%时,所制PLA/MgO薄膜具有最高的拉伸强度和断裂伸长率,这归功于纳米MgO在PLA基体内的分散均一性。     

PLA/P34HB共混纤维的制备与性能

采用熔融纺丝法制备了聚乳酸（PLA）/聚（3-羟基丁酸酯-co-4-羟基丁酸酯）（P34HB）共混纤维,分析了P34HB含量对PLA/P34HB共混纤维热学性能、结晶性能和力学性能的影响,并研究了拉伸倍数对P34HB含量为30%(w)的共混纤维性能的影响。结果表明：当拉伸倍数为3倍时,随着P34HB含量的增加,PLA/P34HB共混纤维的结晶度逐渐降低,断裂强度和初始模量逐渐下降,而断裂伸长率逐渐增大;随着拉伸倍数的增大,P34HB含量为30%(w)的PLA/P34HB共混纤维的结晶度、断裂强度和初始模量逐渐提高,断裂伸长率逐渐降低,当拉伸8倍时,共混纤维的断裂强度达到425 MPa,断裂伸长率为15.5%,初始模量为7 005 MPa。     

PLA/PBAT薄膜的制备及其降解性能研究

以过氧化二苯甲酰(BPO)为界面相容剂,采用熔融挤出、吹塑成型的方法制备了聚乳酸/己二酸-对苯二甲酸-丁二酯共聚物(PLA/PBAT)薄膜。通过力学性能检测和碱液加速降解试验研究了PBAT含量对PLA/PBAT薄膜力学性能及降解速率的影响;并运用红外光谱(FTIR)及动态力学分析(DMA)探究了降解机理。结果表明:随着PBAT含量的增加,PLA/PBAT复合薄膜的拉伸强度、拉伸模量及直角撕裂强度减小,断裂伸长率增大。PLA/PBAT复合薄膜的降解实质是酯键的水解。与降解前相比,降解后薄膜的储能模量大幅度降低,玻璃化转变温度略微下降。     

PGA/PBAT复合材料的性能及应用研究

采用熔融共混法制备了一系列不同组分含量的聚乙醇酸（PGA）/聚对苯二甲酸-己二酸丁二醇酯（PBAT）复合材料，对复合材料的耐热性能、力学性能和水气阻隔性能进行了表征。结果表明，当PGA含量为80 %（质量分数，下同）时，注塑样条的拉伸强度为68.80 MPa、断裂伸长率为72.15 %、冲击强度为16.00 kJ/m²、负荷变形温度为120 °C，表明该复合材料可用于制备一次性餐具；当PGA含量为20 %时，吹塑薄膜的纵横向拉伸强度均在25 MPa以上，纵横向断裂伸长率均在600 %以上，表明该复合材料可用于生产膜袋产品；此外，随着PGA含量的增加，PGA/PBAT材料的水气阻隔性能也逐渐增加，其中含20 %PGA的PGA/PBAT复合膜的水蒸气透过率为纯PBAT薄膜的1/7。     

功能化纳米纤维素复合PLA/PBAT薄膜的制备及性能

以γ-氨丙基三乙氧基硅烷(KH550)为改性剂对纤维素纳米纤维(CNF)进行功能化改性，并用聚丙二醇(PPG)对改性后的CNF进行包覆，制备了CNF-PPG纳米粒子。将其作为填料加到聚乳酸(PLA)/聚己二酸/对苯二甲酸丁二醇酯(PBAT)聚合物基体中，用溶液浇铸法制备了PLA/PBAT/CNF-PPG复合薄膜。通过FTIR、XPS、SEM、DSC、TG对薄膜进行了表征，探讨了PLA与PBAT的质量比及CNF-PPG纳米粒子的添加量对复合薄膜机械强度、热稳定性、阻隔性能的影响。结果表明，PLA/PBAT薄膜比纯PLA薄膜具有更高的韧性和热稳定性；当m(PLA)∶m(PBAT)=90∶10、CNF-PPG纳米粒子用量(以PLA和PBAT的质量为基准，下同)为10%时，PLA/PBAT/CNF-PPG(90/10/10)复合薄膜的拉伸强度达到(33.38±0.64) MPa，断裂伸长率为39.97%±0.67%；复合薄膜最终降解温度从纯PLA膜的394℃提高到435℃；复合薄膜的水蒸气和氧气透过系数分别为4.98×10^–14 g·cm/(cm²·...     

改性木聚糖对PBAT/PLA复合材料包装性能的影响

通过硅烷偶联剂KH560对木聚糖（xylan）进行改性，采用熔融共混制备聚己二酸/对苯二甲酸丁二酯（PBAT）/聚乳酸（PLA）/xylan复合薄膜，探讨了不同含量的xylan和改性木聚糖（s-xylan）对薄膜的力学性能和透氧、透湿、透光等性能的影响。结果表明，复合薄膜的拉伸强度和氧气透过率在当s-xylan含量为1 %（质量分数，下同）时达到最佳效果，其中拉伸强度较纯PBAT/PLA薄膜提高了11.7 %，氧气透过率比纯PBAT/PLA薄膜的氧气透过系数降低了32.7 %；s?xylan复合薄膜的阻湿能力明显优于未改性xylan复合薄膜，同时复合薄膜雾度随着xylan含量的增加而增大。     

PBAT/PLA薄膜的制备及性能研究

将聚乳酸（PLA）和聚对苯二甲酸-己二酸-丁二醇酯（PBAT）共混制备成共混材料,探讨了不同PLA含量对材料性能的影响。结果表明,PBAT/PLA共混材料中,随着PLA含量的增加,拉伸强度先降低后升高,当PLA含量为90 %时,拉伸强度达到60.12 MPa,而其断裂伸长率从703 %降低至8 %,由韧性材料逐渐转变为脆性材料;PLA含量为30 %时,性能变化出现拐点;PLA含量为50 %时出现明显相分离,且PLA的加入可以加速PBAT材料的结晶,使结晶温度由38 ℃提高至82 ℃;PBAT/PLA共混材料在PLA含量低于70 %时,都可以实现较好的吹膜过程,且薄膜材料的拉伸强度为39.59 MPa,断裂伸长率不低于137 %。     

纳米纤维素的表面修饰及对聚乳酸膜的力学性能和阻隔性能的影响

本实验通过化学水解法从农林废弃物油茶果壳中提取出油茶果壳纳米纤维素（cellulose nanocrystals, CNC）,经丁酸酐表面修饰获得丁酸酯化纳米纤维素（butyrated cellulose nanocrystals, BCNC）后,通过溶液浇铸法制备得到了BCNC/聚乳酸（PLA）复合材料,研究了CNC改性后的形貌及性能变化,以及BCNC对PLA力学性能、阻隔性能及透光率的影响。研究结果表明,经改性后,纳米纤维素的团聚现象得到改善并能稳定的分散在非极性有机溶剂中。在PLA复合材料中,BCNC对PLA有增强增韧的效果,添加5 wt%的BCNC时,PLA膜的拉伸强度提升了30.1%。添加5 wt%的BCNC,PLA复合膜的水蒸气透过率和氧气透过率分别下降了60.0%和35.0%,且仍具有较高的透光率。由于BCNC在基体中有更好的分散性和界面结合,对提升PLA力学性能和阻隔性能的效果均优于CNC。     

Synthesis and chain extension of hydroxyl‐terminated poly(lactic acid) oligomers and application in the blends

Hydroxyl‐terminated poly(lactic acid) prepolymer (LA prepolymer) were prepared via L ‐lactic acid as monomer, 1,4‐butanediol as blocking agent and Sn(II) octoate as catalyst by direct melt polymerization. Then the LA prepolymer was blended with starch followed by in situ chain extending reaction using different content of TDI as chain extender, producing the high molecular weight of poly(ester urethane) in the blends. The LA prepolymer/starch‐TDI blends were characterized by GPC, ¹H‐NMR, SEM, DSC, tensile strength testing, and water resistance. The SEM results of cross‐section show that, compared with the simple PLA/starch blends, almost the starch granules were completely covered by ploy(ester urethane) in the LA prepolymer/starch‐TDI blends system. In comparison to the simple PLA/starch blends, the mechanical properties of LA prepolymer/starch‐TDI blends were increased, such as tensile strength increasing from 18.6 ± 3.8 to 44.2 ± 6.2 Mpa, tensile modulus increasing from 510 ± 62 to 1,850 ± 125 Mpa and elongation at break increasing from 1.8 ± 0.4 to 4.0 ± 0.5 %, respectively. This is attributed to high weight of poly (ester urethane) was formed via in situ reaction of the end of hydroxyl (LA prepolymer) and isocyanate groups and the starch granules were easily covered by ploy(ether urethane) via in situ polymerization in the blends. Moreover, covalent linkage was formed between the two phases interfaces. As a result, the interfacial adhesion was enhance and improved the mechanical property. In addition, the water resistance of LA prepolymer/starch‐TDI blends was much better that of the simple PLA/starch blends. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers     

Blends of polylactic acid and arylated soy protein isolate with triacetine as plasticiser

Abstract

Blends of polylactic acid (PLA) and arylated soy protein isolate (ASPI) were successfully prepared by the extrusion process followed by injection moulding. To improve the interfacial adhesion between PLA and ASPI powder, mandelic acid as an amphiphilic additive was incorporated. Rheological and thermal characterisations of PLA/ASPI blends were performed on rheometer, differential scanning calorimeter and thermogravimetric analyser. Thermomechanical characterisation of PLA/ASPI blends was carried out on a dynamic mechanical analyser. Tensile and flexural modulus of PLA/ASPI blends increased compared to neat PLA. Different amounts (5–15 wt-% wrt PLA/ASPI blends) of plasticiser was added to PLA/ASPI blends containing 2·5 wt-% of ASPI. Results indicated that at 10 wt-% of plasticiser, PLA/ASPI blends showed maximum tensile strength of ～8·8 MPa as well as appreciable elongation at break. Morphological studies of PLA/ASPI blends at different amounts of plasticiser were also carried out by scanning electron microscope.     

Mechanical properties of poly(lactic acid) and wheat starch blends with methylenediphenyl diisocyanate

Poly(lactic acid) (PLA) and wheat starch are biodegradable polymers derived from renewable sources. A previous study showed that thermally blending starch and PLA in the presence of methylenediphenyl diisocyanate (MDI) enhanced the mechanical properties of the blends. In this work, blends of PLA with various levels of wheat starch and MDI were hot mixed at 180°C then hot‐pressure molded at 175°C to form test specimens. The blends were characterized for mechanical properties, fracture microstructure, and water absorption. Pure PLA had a tensile strength of 62.7 MPa and elongation of 6.5%. The blend with 45% wheat starch and 0.5 wt % MDI gave the highest tensile strength of about 68 MPa with about 5.1% elongation. The blend with 20% starch and 0.5 wt % MDI had the lowest tensile strength of about 58 MPa with about 5.6% elongation. Dynamic mechanical analysis showed that storage modulus increased and tan δ decreased as starch level increased, but almost leveled off when starch level reached 45% or higher. Water absorption of the blends increased significantly with starch content. Yet the blend, if water proofed on its surface, has potential for short‐term disposable applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1257–1262, 2002; DOI 10.1002/app.10457     

Crosslinked poly(vinyl alcohol) and starch composite films: Study of their physicomechanical,thermal, and swelling properties

Crosslinked poly(vinyl alcohol) was blended with 10, 20, 40, and 50 wt % starch by a solution‐casting process. The solution‐cast films were dried, and then their physicomechanical properties including tensile strength, tensile elongation, tensile modulus, tear strength and density, and burst strength and density were tested. Thermal analysis was performed by differential scanning calorimetry. A moisture analysis of the PVA/starch films was performed and their moisture content determined. Also investigated were the films'resistance to solubility in water, 5% acetic acid, 50% ethanol, and sunflower oil and their swelling characteristics in 50% ethanol and sunflower oil. The prepared PVA/starch blends showed significant improvement in tensile modulus and in resistance to solubility in water, 5% acetic acid, and 50% ethanol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1127–1132, 2007     

Crosslinked poly(vinyl alcohol) and starch composite films. II. Physicomechanical,thermal properties and swelling studies

Poly(vinyl alcohol) (PVA) was blended with 10, 20, 30, 40, and 50 wt % of starch with and without crosslinking by solution casting process. The solution‐casted films were dried and tested for physicomechanical properties like tensile strength, tensile elongation, tensile modulus, tear and burst strengths, density, and thermal analysis by differential scanning calorimetry (DSC). These PVA/starch films were further characterized for moisture content; solubility resistance in water, 5% acetic acid, 50% ethanol, and sunflower oil; and swelling characteristics in 50% ethanol and sunflower oil. The crosslinked PVA/starch composite films show significant improvement in tensile strength, tensile modulus, tear and burst strengths, and solubility resistance over the uncrosslinked films. Between the crosslinked and uncrosslinked films, the uncrosslinked films have higher tensile elongation, moisture content, moisture absorption, and swelling over the crosslinked films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 909–916, 2007     

Thermal and mechanical properties of poly(lactic acid)/starch/methylenediphenyl diisocyanate blending with triethyl citrate

Triethyl citrate (TC) was added as a plasticizer to a blend of poly(lactic acid) (PLA) and starch in the presence of methylenediphenyl diisocyanate (MDI). As expected, TC improved the elongation at break and toughness and, at the same time, decreased the tensile strength and modulus. However, TC did not significantly affect the coupling effects of MDI on starch and PLA. The tensile strength of the blend with MDI was much greater than the tensile strength without MDI at the same TC level. The tensile properties of the blend changed dramatically as the TC concentration increased from 5 to 12.5%. At a TC concentration of 7.5%, the blend produced desirable elongation and toughness with fairly good tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2947–2955, 2003     

Preparation and mechanical characterization of chicken feather/PLA composites

Green composites, a bio‐based polymer matrix is reinforced by natural fibers, are special class of bio‐composites. Interest about green composites is continuously growing because they are environment‐friendly. This study describes the preparation and mechanical characterization of green composites using polylactic acid (PLA) matrix including chicken feather fiber (CFF) as reinforcement. Extrusion and an injection molding process were used to prepare CFF/PLA composites at a controlled temperature range. CFF/PLA composites with fiber mass content of 2%, 5%, and 10% were manufactured. The effects of fiber concentration and fiber length on mechanical properties of CFF/PLA composites have been studied. Mechanical properties of composites were investigated by tensile, compression, bending, hardness, and Izod impact testing. The results of experiments indicated that Young's modulus, compressive strength, flexural modulus, and hardness of the PLA reinforced CFF composites are higher but tensile strength, elongation at break, bending strength and impact strength of them are lower than pure PLA. The results indicate that these types of composites can be used for various applications. POLYM. COMPOS., 38:837–845, 2017. © 2015 Society of Plastics Engineers     

Mechanical properties and crystallization behavior of poly(lactic acid) blended with dendritic hyperbranched polymer

Mechanical properties of poly(lactic acid) (PLA) blended with a small amount of dendritic hyperbranched polymer (DHP) were investigated. Effects of DHP and starch on mechanical properties of PLA were compared. DHP significantly improved tensile strength and elongation at break of PLA. A small amount of starch in PLA slightly improved PLA's elongation, but had no effect on tensile strength. Isothermal crystallization kinetics of PLA blended with DHP and starch were also studied. Both DHP and starch acted as nucleation agents and significantly increased crystallization rate and crystallinity of PLA. Copyright © 2004 Society of Chemical Industry     

Effect of oxidation level on the dual modification of banana starch: The mechanical and barrier properties of its films

Banana starch was oxidized at three different levels and then acetylated. The double‐modified starch was used for film preparation. The physical, mechanical, and barrier properties were tested. The oxidation level increased the whiteness of the film, and the second modification (acetylation) did not affect this parameter. The solubility increased with temperature and oxidation level. However, acetylation decreased the solubility value. At the longest storage times, the solubility decreased because of starch reorganization inside the polymeric matrix. In general, oxidation increased the tensile strength of the films, and a slight increase was observed when the oxidized starch was acetylated. This effect was more noticeable at the longest storage time. The oxidation level decreased the percentage elongation at break, and a slight effect due to acetylation was observed. The film of oxidized–acetylated starch showed a higher elastic modulus value than its oxidized counterpart. The water vapor permeability increased with oxidation level, but the acetylation decreased this parameter. The oxidation increased the hydrophilic character of the starch because of the formation of carbonyl and carboxyl groups that showed more affinity for water molecules. When the oxidized banana starch was acetylated, a decrease in the water vapor permeability was found because the acetylation increased the hydrophobic character of the starch due to the ester group. Films prepared with the double‐modified banana starch had some improved physical, mechanical, and barrier properties, and they may be used in specific applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Antioxidant,antifungal, water binding,and mechanical properties of poly(vinyl alcohol) film incorporated with essential oil as a potential wound dressing material

In this study, the properties of poly (vinyl alcohol) (PVA) films incorporated with Zataria multiflora essential oil (ZMO) as a potential antioxidant/antibacterial material was investigated. PVA films were prepared from PVA solutions (2% w/v) containing different concentrations of ZMO. Water solubility, moisture absorption, water swelling, and water vapor permeability for pure PVA films were 57 ± 1.1, 99 ± 3.2%, 337 ± 8%, and 0.453 ± 0.015 g mm/m² h, respectively. Incorporation of ZMO into PVA films caused a significant decrease in water swelling and moisture absorption and increase in solubility and water vapor permeability. Tensile strength, elastic modulus, and elongation at break for pure PVA films were 13.5 ± 0.61 MPa, 15.2 ± 0.8 MPa, and 216 ± 4%, respectively. Incorporation of ZMO into the PVA films caused a significant decrease in tensile strength and elastic modulus and increase in elongation at break of the films. Pure PVA film showed UV‐visible light absorbance ranging from 280 to 440 nm with maximum absorbance at 320 nm. Addition of ZMO caused a significant increase in light absorbance and opacity. PVA films exhibited no antioxidant and antifungal activities, whereas PVA/ZMO films exhibited excellent antioxidant and antifungal properties. Although the bioactivity PVA films were improved by the addition of ZMO, however, the mechanical properties and water binding capacity of the films were weaken slightly. Thus, ZMO emulsified in the ethanol not compatible with PVA matrix and more suitable emulsifier was needed in order to obtain strong film with higher mechanical properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40937.