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。     

聚乳酸/酯化纤维素/纳米CaCO3复合材料的制备与表征

采用熔融共混法制备了聚乳酸(PLA)/酯化纤维索/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...     

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。     

碳酸钙对PBAT/PLA复合材料性能的影响

采用碳酸钙(CaCO3)对聚己二酸-对苯二甲酸丁二酯(PBAT)/聚乳酸(PLA)复合材料进行改性,并通过吹膜法成功制备出PBAT/PLA/CaCO3共混薄膜,并采用热重、差示扫描量热、流变性能和力学性能等一系列测试研究了CaCO3对PBAT/PLA复合材料的影响.结果表明,CaCO3的加入大大增加了PBAT/PLA复...     

PLA协同纳米CaCO3增韧PP的研究

通过熔融共混制得聚丙烯/聚乳酸/纳米碳酸钙（PP/PLA/CaCO3）复合材料,考察了PLA和纳米CaCO3对复合材料力学性能、热性能、流变性能与结晶形态的影响及其作用机理。结果表明,复合材料中形成连续空间网络结构的PLA有助于改善PP的性能,PLA含量为20 %（质量分数,下同）时复合材料综合力学性能最佳;与纯PP相比,加入PLA后的复合材料拉伸强度和冲击强度分别提高5.1 %和54.4 %,断裂伸长率降低62.5 %;纳米CaCO3通过“滚珠增韧”和“异相成核”作用明显改善复合材料力学性能,纳米CaCO3含量15 %时产生的晶粒细化作用效果最为显著,复合材料综合力学性能达到最佳,拉伸强度、断裂伸长率和冲击强度分别比未添加CaCO3时提升了15.2 %、2.7 %和5.6 %。     

聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙复合材料的性能研究

采用熔融共混法制备了聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙（PLA/EVA/CaCO3）复合材料,利用差示扫描量热仪、X射线衍射仪、偏光显微镜、扫描电子显微镜、力学性能测试和热变形温度测试等手段,研究了EVA和CaCO3对复合材料的结晶性能、断面形貌、力学性能和耐热性能的影响。结果表明,EVA 具有增韧作用,但降低了复合材料的强度和耐热性;而CaCO3可以提高复合材料的强度、韧性、结晶性能和耐热性能;CaCO3与EVA的加入对PLA有协同增韧作用,且不改变PLA的晶型;当PLA/EVA=90/10,加入10 %（质量分数,下同）的CaCO3时,复合材料有最佳的综合性能。     

用于3D打印的微晶纤维素/聚乳酸复合材料制备与性能研究

以微晶纤维素（MCC）为增强材料、聚乳酸（PLA）为基体,通过高温熔融共混、挤出、拉丝等流程,制备适用于熔融沉积成型（FDM）3D打印技术的MCC/PLA复合材料,并通过FDM型3D打印机打印出成品。讨论了MCC添加量对该复合材料的力学性能、热性能、微观结构以及3D打印性能的影响。研究结果表明,随着MCC添加量的增加,复合材料的力学性能呈现先增高后下降的变化趋势,当MCC添加量为3%时,其拉伸强度和弯曲强度达到最高,分别为54.55 MPa和64.25 MPa。红外分析证实了微晶纤维素与聚乳酸在熔融时发生了接枝共聚反应。热性能分析表明,添加少量MCC,可以提高复合材料的热稳定性和PLA的结晶度。MCC添加量为3%的MCC/PLA复合材料其力学性能、打印性能和外观达到最佳,可应用于FDM型3D打印技术。     

细菌纤维素及其酯化产物与聚乳酸的复合材料的制备与表征

细菌纤维素(BC)经由多种有机酸(乙酸、正己酸、月桂酸)表面酯化,得到细菌纤维素乙酸酯(C2-BC)、细菌纤维素正己酸酯(C6-BC)、细菌纤维素月桂酸酯(C12-BC),将BC及酯化产物分别加入到聚乳酸(PLA)溶液,采用热致相分离技术(TIPS)制备出BC(BC酯化产物)/PLA复合材料,红外光谱、扫描电镜、差热分析和热重分析结果显示,BC以及酯化产物均匀分布在PLA中,制备的复合材料具有多孔结构,酯化产物的添加提高了PLA的结晶度,但是对PLA链的移动性没有太大影响。同时,BC及其酯化产物的的引入,提高了PLA的降解温度,并且随着酯化支链的长度增加,杨氏模量和抗拉强度也相应有所提高。     

纳米纤维素协同聚氨酯增强增韧聚乳酸的研究

以聚乳酸（PLA）为基体、聚氨酯（PU）为增韧相、纳米纤维素（NCF）为增强相,通过溶液法与熔融共混制得PLA/PU/NCF复合材料,研究了PU和NCF的含量对PLA力学性能与热稳定性的影响。采用傅里叶变换红外光谱仪、热失重分析仪、扫描电子显微镜和力学性能测试手段对PLA/PU/NCF复合材料的结构和性能进行了表征和分析。结果表明,柔顺的PU分子限制了PLA的结晶,提升了PLA基体的韧性;刚性的NCF通过氢键作用提升了PLA基体的强度;当NCF含量为3 %、PU含量为17 %时,PLA/PU/NCF复合材料的拉伸强度和断裂伸长率比纯PLA提升了12.10 %和694.91 %;高温热稳定性有了显著改善,复合材料的600 ℃残炭率为19.36 %。     

碳酸钙填充PLA复合材料的制备和性能研究

用熔融共混法制备了聚乳酸/碳酸钙（PLA/ CaCO3）复合材料,研究了PLA/ CaCO3复合材料的力学性能、热性能、结构及断裂机理。结果表明：较高含量的CaCO3在材料内部形成网络结构,阻止了微裂纹的扩展,断裂从脆性变为韧性,对PLA起到了较为明显的增韧作用;但当CaCO3的含量较低时,填料CaCO3粒子孤立地分散在基体内,未形成网络结构,微裂纹的扩展不能及时被阻止,会形成裂纹,从而导致材料破坏,使冲击强度下降;CaCO3的引入使复合材料的熔融峰出现了双峰,复合材料的结晶性能有所提升,使复合材料的耐热性能提高。     

Enhancing the mechanical properties of 3D printed polylactic acid using nanocellulose

We report here a systematic investigation of the mechanical properties of polylactic acid (PLA) processed by fused filament fabrication (FFF) 3D printing vs PLA processed by compression molding. Our results show that the tensile strength and modulus of FFF-PLA is 49% and 41% lower, respectively, than compression molded samples of PLA. We also demonstrate here an approach to augment the mechanical properties of 3D printed PLA using nanocellulose. Incorporation of a small quantity (1 wt%) of cellulose nanofibers (CNF) was found to enhance the tensile strength and modulus of 3D printed PLA by 84% and 63%, respectively. X-ray microtomography was used to probe the morphology of 3D printed PLA and PLA/CNF composites. 3D printed PLA/CNF composites had significantly lesser voids as compared to neat 3D printed PLA. Differential scanning calorimetry study revealed that CNF can accelerate the nucleation and crystallization of 3D printed PLA leading to enhanced crystallinity. The thermal stability of 3D printed PLA/CNF composites was not compromised by the addition of CNF. The enhanced mechanical properties of 3D printed PLA/CNF composites can be ascribed to higher crystallinity and lesser defects.     

Reinforcing effect of nanocrystalline cellulose and office waste paper fibers on mechanical and thermal properties of poly (lactic acid) composites

Nanocrystalline cellulose (NCC) was prepared from office waste paper (OWP) by sulfuric acid hydrolysis method in this paper and it was used to prepare a series of poly (lactic acid) PLA/NCC composites by using a dissolution method in solvent N, N-dimethylformamide solution. The results indicated that with the addition of only 3 wt% NCC, the composites exhibited outstanding mechanical property. The tensile, bending and impact properties of the PLA/3NCC composite were improved by 8.2%, 13.1%, and 35.9% than those of pure PLA, respectively. On this basis, office waste paper fibers (OWF) were also used as a physical blended filler to enhance PLA/NCC composites to reduce the preparation cost of PLA composites and the perfect PLA/NCC/OWF sample was easily manufactured by melting–blending and injection molding. According to the crystallization and melting performance table, both NCC and OWF can act as nucleating agent to promote the crystallization properties on composites, while the blends did not have positive effect on thermal stability. Furthermore, the water absorption and degradation properties of PLA composites were also studied. This work not only provided a novel idea for the utilization of office waste paper but also successfully produced environment friendly composites with favorable mechanical properties and crystallization performance.     

三种植物纤维填充聚乳酸复合材料性能对比

为充分利用农作物植物资源,以稻秸秆、麦秸秆、稻壳三种植物纤维为填充相,聚乳酸(PLA)为基体,制备了PLA/植物纤维复合材料。对三种植物纤维的成分进行了对比分析,并对制备的复合材料的力学性能和吸水性能进行了比较,分析了三种复合材料的热重曲线、差示扫描量热曲线与红外光谱,并用扫描电子显微镜观察了复合材料的断面微观结构。结果表明,三种植物纤维材料中稻秸秆的纤维素与半纤维素总含量最高,稻秸秆制备的PLA复合材料力学性能与界面结合性最好,其弯曲强度为28 MPa,分别比麦秸秆和稻壳制备的PLA复合材料高75%和47%;PLA/稻壳复合材料的吸水率最小,比PLA/稻秸秆和PLA/麦秸秆分别小10%与25%;三种植物纤维改性PLA复合材料的热分解曲线基本相同,PLA/稻壳复合材料的热稳定性相对最好。     

聚乳酸/纤维素共混复合材料的研究进展

叙述了天然纤维、改性纤维、纤维素衍生物与聚乳酸(PLA)复合材料的最新研究现状,围绕共混复合材料的相容性、分散性、力学性能以及应用等方面存在的优缺点,详细介绍了乙基纤维素(EC)、纤维素酯、羧甲基纤维素这3种纤维素衍生物与PLA共混制成复合材料,为纤维素/PLA共混复合材料的研发与应用提供参考。     

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。     

聚己内酯/酯化淀粉/纳米碳酸钙复合材料的制备及性能

以玉米淀粉(ST)和马来酸酐为原料,采用干法改性方法制备了酯化淀粉(EST),将EST与聚己内酯(PCL)、纳米碳酸钙通过密炼机混炼制备可降解PCL/EST/纳米碳酸钙复合材料。利用红外光谱仪、扫描电子显微镜、广角X射线衍射仪和热重-差示扫描量热同步热分析仪研究了PCL/EST/纳米碳酸钙复合材料的微观形态、力学性能、结晶以及热性能。结果表明,随着纳米碳酸钙含量的增加,PCL/EST/纳米碳酸钙复合材料的拉伸强度先升高后降低,当纳米碳酸钙含量为6份(质量份数,下同)时材料的拉伸强度和断裂伸长率达到最大值,与未添加纳米碳酸钙的复合材料相比分别提高了49.8%和34.8%;与PCL/ST/纳米碳酸钙复合材料相比,PCL/EST/纳米碳酸钙复合材料中淀粉颗粒尺寸减小,复合材料的熔点和结晶度有所提高,拉伸强度和熔体流动速率增加,热分解温度下降。     

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     

Mechanical properties of biodegradable composites from poly lactic acid (PLA) and microcrystalline cellulose (MCC)

Biodegradable composites were prepared using microcrystalline cellulose (MCC) as the reinforcement and polylactic acid (PLA) as a matrix. PLA is polyester of lactic acid and MCC is cellulose derived from high quality wood pulp by acid hydrolysis to remove the amorphous regions. The composites were prepared with different MCC contents, up to 25 wt %, and wood flour (WF) and wood pulp (WP) were used as reference materials. Generally, the MCC/PLA composites showed lower mechanical properties compared to the reference materials. The dynamic mechanical thermal analysis (DMTA) showed that the storage modulus was increased with the addition of MCC. The X‐ray diffraction (XRD) studies on the materials showed that the composites were less crystalline than the pure components. However, the scanning electron microscopy (SEM) study of materials showed that the MCC was remaining as aggregates of crystalline cellulose fibrils, which explains the poor mechanical properties. Furthermore, the fracture surfaces of MCC composites were indicative of poor adhesion between MCC and the PLA matrix. Biodegradation studies in compost soil at 58°C showed that WF composites have better biodegradability compared to WP and MCC composites. The composite performances are expected to improve by separation of the cellulose aggregates to microfibrils and with improved adhesion. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2014–2025, 2005