Ludueña L, Vázquez A, Alvarez V
Research Institute of Material Science and Technology (INTEMA), Engineering Faculty, National University of Mar del Plata, Juan B. Justo 4302, (B7608FDQ) Mar del Plata, Argentina.
INTECIN (UBA-CONICET), Department of Civil Engineering, Engineering Faculty, University of Buenos Aires, Las Heras 2214, (C1063ACV) Buenos Aires, Argentina.
Carbohydr Polym. 2012 Jan 4;87(1):411-421. doi: 10.1016/j.carbpol.2011.07.064. Epub 2011 Aug 5.
This study was based on the influence of lignocellulosic fillers and content on the morphology, crystallization behavior and thermal, mechanical and barrier properties of fully biodegradable eco-composites based on polycaprolactone for packaging applications. The biodegradation in soil as a function of time was also analyzed. Composites with 5 and 15wt% of cotton (CO); cellulose (CE) and hydrolyzed-cellulose (HCE) were prepared by melt-mixing. It was determined that, whereas lower content of CO and CE produced a decrease on the crystallinity of the matrix, HCE did not affect it. Increasing the filler content, the crystallinity degree of the matrix decreased at less extent, which was independent on the filler type. A clear reduction on the theoretical melting point, attributed to heterogeneous nucleation sites, took place for the lower content of CO and CE. Induction and half-crystallization times diminished when fillers were incorporated but the effect was less notorious at higher filler contents. All fillers enhanced the Young's modulus of the matrix but the optimal mechanical properties were not obtained with HCE, as was expected, but with CE. After analyzing the main parameters that affect the mechanical properties of the composite; such as morphology, hydrophilicity, crystallinity, mechanical properties and thermal stability of the fillers themselves, interface interaction, filler dispersion and thermal aspects of the composites, we concluded that the parameters responsible for such behavior were the larger aspect ratio, better dispersion and enhanced interface interaction of the CE filler. These parameters also affected the barrier properties and the process of biodegradation in soil of the composites.
本研究基于木质纤维素填料及其含量对基于聚己内酯的完全可生物降解生态复合材料的形态、结晶行为以及热性能、机械性能和阻隔性能的影响，该复合材料用于包装应用。还分析了其在土壤中的生物降解随时间的变化情况。通过熔融共混制备了含有5wt%和15wt%棉（CO）、纤维素（CE）和水解纤维素（HCE）的复合材料。结果表明，较低含量的CO和CE会使基体的结晶度降低，而HCE则不会影响。随着填料含量增加，基体结晶度的降低幅度较小，且这与填料类型无关。对于较低含量的CO和CE，由于异质成核位点，理论熔点明显降低。加入填料后诱导期和半结晶时间缩短，但在较高填料含量时这种影响不太明显。所有填料均提高了基体的杨氏模量，但正如预期的那样，最佳机械性能并非由HCE获得，而是由CE获得。在分析了影响复合材料机械性能的主要参数后，如填料本身的形态、亲水性、结晶度、机械性能和热稳定性、界面相互作用、填料分散以及复合材料的热性能等，我们得出结论，导致这种行为的参数是CE填料具有更大的长径比、更好的分散性和增强的界面相互作用。这些参数也影响了复合材料的阻隔性能以及在土壤中的生物降解过程。
