聚乳酸/纤维素及其衍生物共混复合材料的研究进展

介绍了聚乳酸(PLA)/纤维素、PLA/天然植物纤维、PLA/纤维素酯和PLA/纤维素醚共混复合材料最新的研究进展,综述了复合材料在相容性、分散性、力学性能和降解特性等方面存在的优点和缺点,为此类共混复合材料的进一步研究指明方向。     

羟丙甲纤维素增韧聚乳酸复合材料的制备及性能研究

选用羟丙甲纤维素(HMC)对聚乳酸(PLA)进行增韧改性,采用共混法制备了PLA/HMC复合材料,并对其流变性能、力学性能和结晶性能进行了系统分析.结果表明,PLA/HMC复合材料的表观黏度随剪切速率、温度和HMC含量的增加呈现逐渐下降的趋势;HMC在PLA基体中能够均匀分散,且PLA与HMC之间具有较好的相容性;PL...     

碳酸钙对聚乳酸/酯化纤维素复合材料性能的影响

采用熔融共混工艺制备了聚乳酸(PLA)/酯化纤维素/CaCO3复合材料,通过力学性能测试、热重分析、凝胶渗透色谱和红外光谱分析,研究了CaCO3对复合材料力学性能和热稳定性的影响。结果表明:CaCO3能够与酯化纤维素相互作用,并在一定程度上改善复合材料的力学性能,提高复合材料的热稳定性,减缓PLA的热降解。     

纳米SiO_2包覆微晶纤维素对PLA/PBS复合材料性能的影响

以纳米二氧化硅(nano-SiO_2)表面包覆的微晶纤维素(MCC)为填料,采用熔融共混的方法制备了聚乳酸/聚丁二酸丁二醇酯(PLA/PBS)复合材料。运用扫描电子显微镜、热重分析仪、差示扫描量热仪、动态热力学分析仪等方法研究了nano-SiO_2对PLA/PBS/MCC复合材料的力学性能、热稳定性以及结晶行为的影响。结果表明,nano-SiO_2包覆在MCC表面后与PLA/PBS熔融共混提高了nano-SiO_2在聚合物材料中的分散性,改善了MCC与树脂基体的相容性;添加5%(质量分数,下同)MCC的PLA/PBS/MCC复合材料,与同样添加量的PLA/PBS/nano-SiO_2-MCC复合材料相比,其储能模量、冲击强度以及结晶度分别提高了13.04%、11.70%、71.92%。     

表面改性MCC对PLA复合材料力学与热稳定性能的影响

采用硅烷偶联剂(γ-甲基丙烯酰氧基丙基三甲氧基硅烷,KH-570)和纳米羟基磷灰石(n-HA)分别对微晶纤维素(MCC)表面处理.运用熔融共混方法制备改性微晶纤维素/聚乳酸(MCC/PLA)复合材料.研究了不同的MCC表面改性方法对MCC/PLA复合材料力学性能和热稳定性能的影响.结果表明:硅烷偶联剂KH-570化学包...     

纳米纤维素/聚乳酸/聚乙二醇三元复合材料的研究

将纳米纤维素(NCC)与聚乙二醇(PEG)、聚乳酸(PLA)共混制备出可生物降解的纳米纤维素/聚乳酸复合材料。考察了复合材料的力学性能、降解性和热稳定性能,结果表明:加入2%的纳米纤维素对复合材料有明显的增塑和增强效果;对复合材料进行TGA检测表明,复合材料的热稳定性较纯聚乳酸有所下降;由SEM检测看出,复合材料的柔韧性得到提高,从降解性能分析中看出,复合材料的降解速率随着纳米纤维素质量分数的增加而增加。     

纳米SiO2包覆微晶纤维素对PBS/PLA复合材料性能的影响

以纳米二氧化硅(nano-SiO2)表面包覆的微晶纤维素(MCC)为填料,采用熔融共混的方法制备了聚乳酸/聚丁二酸丁二醇酯（PLA/PBS）复合材料。运用扫描电子显微镜、热重分析仪、差示扫描量热仪、动态热力学分析仪等方法研究了nano-SiO2对PLA/PBS/MCC复合材料的力学性能、热稳定性以及结晶行为的影响。结果表明,nano-SiO2包覆在MCC表面后与PLA/PBS熔融共混提高了nano-SiO2在聚合物材料中的分散性,改善了MCC与树脂基体的相容性;添加5 %（质量分数,下同）MCC的PLA/PBS/MCC复合材料,与同样添加量的PLA/PBS/nano-SiO2-MCC复合材料相比,其储能模量、冲击强度以及结晶度分别提高了13.04 %、11.70 %、71.92 %。     

原位共聚共混制备改性纤维素聚乳酸复合材料

本文以纤维素与乳酸为原料,辛酸亚锡为催化剂,在乳酸体系中制备纤维素聚乳酸接枝共聚物/聚乳酸(CF-g-PLA/PLA)复合材料。采用IR、XRD、SEM、TG、DSC以及电子万能试验机对复合材料进行了表征和力学性能的测试。实验结果表明,在辛酸亚锡的催化下,乳酸脱水生成的丙交酯成功地对纤维素进行了原位接枝共聚改性,改性纤维素与体系中同时生成的聚乳酸原位共混得到CF-g-PLA/PLA复合材料;改性纤维素与聚乳酸具有较好的界面相容性。随着改性纤维素比例的增加,复合材料的热稳定性略有下降,其Tg则略微提高,弯曲强度有较明显的改善。适量加入纤维素会提高复合材料的拉伸性能,过量反而使得拉伸性能下降。     

微晶纤维素对阻燃聚乳酸复合材料力学性能、阻燃与热稳定性的影响

以经硅烷偶联剂(KH570)处理的微晶纤维素(MCC)为填料,三嗪系膨胀阻燃剂(CFA)与聚磷酸铵(APP)的复配体系为阻燃剂(C-IFR),聚乳酸(PLA)为基体树脂,采用熔融共混方法制备阻燃MCC/PLA复合材料,研究了MCC对阻燃PLA复合材料的力学、阻燃性能、热稳定性的影响。力学试验结果显示,MCC加入使PLA和阻燃PLA均比纯基体树脂的拉伸强度、弯曲强度有所降低,对悬臂梁缺口冲击强度影响小。MCC在小添加量时可以提高PLA复合体系的极限氧指数,MCC与APP具有的协同效应降低了PLA的燃烧速率,提高了材料的成炭性能。热降解动力学表明,MCC增加了PLA和阻燃PLA材料的活化能,提高了PLA复合材料的热稳定性,同时MCC降低PLA的玻璃化转变温度。     

聚乳酸/酯化纤维素复合材料的制备与表征

通过气固反应利用马来酸酐（MA）对纤维素进行酯化改性,采用熔融共混工艺制备了聚乳酸（PLA）/酯化纤维素复合材料。红外分析表明纤维素与MA发生了酯化反应。力学性能测试、热重分析、差示扫描量热仪（DSC）、扫描电镜（SEM）等分析表明,PLA/酯化纤维素复合材料的拉伸模量和弯曲模量随酯化纤维素含量的增加而升高,拉伸强度、弯曲强度和热稳定性随酯化纤维素含量的增加而降低;复合材料的Tc相对纯PLA较高,说明酯化纤维素的加入起到了异相成核作用,使结晶速率提高。酯化纤维素在复合材料中分散充分,但两者的界面黏结力较弱。     

Crystallization behavior of α‐cellulose short‐fiber reinforced poly(lactic acid) composites

The isothermal crystallization behavior of α‐cellulose short‐fiber reinforced poly(lactic acid) composites (PLA/α‐cellulose) was examined using a differential scanning calorimeter and a petrographic microscope. Incorporating a natural micro‐sized cellulose filler increased the spherulite growth rate of the PLA from 3.35 μm/min for neat PLA at 105°C to a maximum of 5.52 μm/min for the 4 wt % PLA/α‐cellulose composite at 105°C. In addition, the inclusion of α‐cellulose significantly increased the crystallinities of the PLA/α‐cellulose composites. The crystallinities for the PLA/α‐cellulose composites that crystallized at 125°C were 48–58%, higher than that of the neat PLA for ～13.5–37.2%. The Avrami exponent n values for the neat and PLA/α‐cellulose composites ranged from 2.50 to 2.81 and from 2.45 to 3.44, respectively, and the crystallization rates K of the PLA/α‐cellulose composites were higher than those of the neat PLA. The activation energies of crystallization for the PLA/α‐cellulose composites were higher than that of the neat PLA. The inclusion of α‐cellulose imparted more nucleating sites to the PLA polymer. Therefore, it was necessary to release additional energy and initiate molecular deposition. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚乳酸/酯化纤维素/纳米CaCO_3复合材料的制备与表征

采用熔融共混法制备了聚乳酸(PLA)/酯化纤维素/纳米CaCO3复合材料,并通过力学性能测试、差示扫描量热仪、热重分析和扫描电镜等测试手段对复合材料的性能进行了表征。结果表明,当酯化纤维素和纳米CaCO3的总含量小于5%时,能够起到较好的增强作用,复合材料的力学性能明显优于纯PLA;酯化纤维素和纳米CaCO3的加入起到了异相成核作用,但会降低复合材料的热稳定性;酯化纤维素在复合材料中分散充分,无聚集现象;但当填料总含量大于10%时,纳米CaCO3发生明显发生聚集。     

Preparation of acylated microcrystalline cellulose using olive oil and its reinforcing effect on poly(lactic acid) films for packaging application

A novel poly(lactic acid) (PLA) based composite, reinforced by microcrystalline cellulose (MCC) was prepared. MCC was modified by esterification reaction using olive oil for improving the compatibility with PLA matrix. The acylated microcrystalline cellulose (AMCC) exhibited reduced polarity in comparison to unmodified MCC. AMCC/ PLA composite films were prepared using solvent casting technique. The effects of the MCC surface modification on morphological, mechanical, physical, thermal, biodegradability and barrier properties of the PLA based MCC composites were studied. FTIR analysis confirmed acylation reaction of MCC. Scanning electron microscopy analysis exhibited a uniform distribution of AMCC in PLA matrix. Barrier properties of AMCC based composites were improved as compared to MCC based composites. The tensile strength and tensile modulus of composite films (at 2 wt.% AMCC) were improved about 13% and 35% as much as those of the pure PLA films, respectively. These biodegradable composite films can be a sustainable utilization of olive oil and microcrystalline cellulose in the food packaging application.     

Cellulose fiber‐reinforced polylactic acid

Polymer composites from polylactic acid (PLA) and two types of cellulose fibers obtained either by acid hydrolysis of microcrystalline cellulose (HMCC) or by mechanical disintegration of regenerated wood fibers (MF) were prepared and characterized. To enhance the compatibility of the cellulose fibers with PLA matrix, a surface treatment based on 3‐aminopropyltriethoxysilane (APS) was performed. The Fourier Transform Infrared (FTIR) spectroscopy was used to determine the chemical groups involved in the surface modification reaction. The silanization treatment resulted in different modifications on both types of cellulose fibers because of their different structural and morphological characteristics. The composites were prepared by incorporating 2.5% of the treated or untreated HMCC and MF into a PLA matrix using a melt‐compounding technique. An improved adhesion between the two phases of the composite materials was observed by scanning electron microscopy thanks to treatment. The dynamic mechanical thermal analyses showed that both untreated and silane treated fibers led to an improvement of the storage modulus of PLA in the glassy state. A higher enhancement of the storage modulus in the case of PLA/HMCC composites than the composites containing MF was obtained as a result of the high aspect ratio of these fibers which allows better matrix‐to‐filler stress transfer. Furthermore, the storage modulus of PLA composites was enhanced by silanization even at higher temperatures especially after thermal treatment. The cellulose fibers addition in PLA matrix modified significantly the relaxation phenomenon as observed in tan δ curves, emphasizing strongly modified molecular mobility of PLA macromolecules and crystallization changes. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers.     

A comparison of partially acetylated nanocellulose,nanocrystalline cellulose,and nanoclay as fillers for high‐performance polylactide nanocomposites

Partially acetylated cellulose nanofibers (CNF) were chemically extracted from sisal fibers and the performance of those CNF as nanofillers for polylactide (PLA) for food packaging applications was evaluated. Three PLA nanocomposites; PLA/CNF (cellulose nanofibers), PLA/CNC (nanocrystalline cellulose), and PLA/C30B (Cloisite^TM 30B, an organically modified montmorillonite clay) were prepared and their properties were evaluated. It was found that CNF reinforced composites showed a larger decrease on oxygen transmission rate (OTR) than the clay‐based composites; (PLA/CNF 1% nanocomposite showed a 63% of reduction at 23°C and 50% RH while PLA/C30B 1% showed a 26% decrease) and similar behavior on terms of water vapor barrier properties with 46 and 43%, respectively of decrease on water vapor transmission rate at 23°C and 50% RH (relative humidity). In terms of mechanical and thermomechanical properties, CNF‐based nanocomposites showed better performance than clay‐based composites without affecting significantly the optical transparency. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43257.     

生物降解聚乳酸合金最新进展及展望

系统论述了生物降解聚乳酸(PLA)合金复合材料的最新研究进展,着重介绍了聚乳酸合金中有巨大商用潜力的完全生物基降解高分子合金体系:PLA/淀粉合金、PLA/纤维素合金、PLA/聚ε-己内酯合金、PLA/聚酰胺合金、PLA/聚羟基脂肪酸酯合金、PLA/壳聚糖合金及PLA/稀土多元复合材料等。并提出利用稀土离子独特的4f电子亚层能级的空轨道与聚乳酸生物基复合材料中的羰基、羟基等含氧官能团配位来改善聚乳酸合金复合材料的综合性能,这为设计开发新型稀土-聚乳酸复合材料提供了新的思路,为聚乳酸产业化进程提供新的契机。     

Preparation and physical properties of polylactide/cellulose nanowhisker/nanoclay composites

Polylactide (PLA) has been getting lots of interests in step with global concerns on sustainable green technology because it is biodegradable with reasonable mechanical strength and can be processed quite easily. But, to compete with commodity polymers in the market PLA‐based green composites need to have higher mechanical and thermal properties. Therefore, in this study, cellulose nanowhiskers (CNWs) as well as nanoclay were used as nanofillers to improve physical properties of PLA. CNWs were prepared from microcrystalline cellulose (MCC) powder by acid hydrolysis, and confirmed by TEM. To improve interfacial bonding between PLA and CNWs maleic anhydride‐grafted PLA (MAPLA) was prepared and used as a compatibilizer. PLA‐based composites were prepared by melt mixing followed by compression molding. Mechanical properties of the composites were measured by UTM and DMA. The melt mixing conditions were optimized first, and then composition was optimized step by step to obtain a PLA‐based green composite with excellent physical properties. CNWs were much better than MCC powder as reinforcing natural fillers. MAPLA and nanoclay could improve considerably physical properties of the PLA‐based composites. Compared to the PLA/MCC composite the tensile strength of the PLA/CNW/MAPLA/nanoclay composite was almost doubled and the glass transition temperature of the composite was 23°C higher, making the composite possible for commercial applications. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers