On Mechanical Behavior of Pine Nut Shell and Polyurethane Derived from Castor Oil Green Composite

ABSTRACT

Natural fibres reinforced polymeric composites are examples of green composites. Commodities polymers derived from fossil sources have volatile organic compounds in their compositions. Polyurethane derived from castor oil is produced from renewable sources, it has no volatile organic compounds in its composition and presents biodegradability. This study aims to evaluate physical-, mechanical- and thermal properties of composites of Araucaria pine nut shell vegetable fibres as reinforcement and polyurethane derived from castor oil (PU) as matrix. The composites were produced with 20 wt.%, 35 wt.% and 50 wt.% of PU. The 100% PU (used as control samples) properties were assessed by flexural strength, thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). Composites panels properties were assessed by the following techniques/approaches volumetric density, water absorption, thickness swelling, flexural strength, TGA, FTIR and scanning electron microscopy (SEM). Composites with 35%PU presented flexural strength of 51.55 MPa, a density of 1018 kg/m³, water absorption of 7.95% and swelling in thickness over 24 hours of 5.36%, these results are better when compared to similar composites made with pine nut shell and thermoset polymer. The study focused on how the fibre-matrix adhesion at the interface plays a role in the composite reinforcement.

摘要

天然纤维增强聚合物复合材料是绿色复合材料的例子. 从化石中提取的聚合物成分中含有挥发性有机化合物. 以蓖麻油为原料制备的聚氨酯是一种可再生资源，不含挥发性有机物，具有生物降解性. 本研究旨在评估以南洋杉松子壳植物纤维为增强体，以蓖麻油衍生之聚胺酯（PU）为基质之复合材料之物理力学及热性能. 用20%,35%和50%的PU制备了复合材料. 用弯曲强度热重分析（TGA）和傅立叶变换红外光谱（FTIR）对100%PU（用作对照样品）的性能进行了评价. 通过体积密度吸水率厚度膨胀率弯曲强度TGA,FTIR和扫描电子显微镜（SEM）等方法对复合材料面板的性能进行了评价. PU含量为35%的复合材料抗弯强度为51.55mpa， 密度为1018kg/m³, 吸水率为7.95%，24小时以上的溶胀率为5.36%，与类似的松子壳和热固性聚合物复合材料相比，这些结果更好. 研究了界面处的纤维-基体粘结在复合材料增强体中的作用.

KEYWORDS:

• Composite
• polyurethane
• castor oil
• pine nut shell
• mechanical properties
• fiber/matrix interface

关键词::

• 复合材料，
• 聚氨酯，
• 蓖麻油
• 松子壳
• 机械性能
• 纤维/基体界面

Acknowledgments

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) -Finance Code 001. The authors would like to thank FAPESP, Fundação Araucária, and CNPQ for financial support. Embrapa Florestas for the equipments and for donating the pine nut shell. Multi-User Center for Materials Characterization - CMCM from UTFPR-CT for the SEM analyses. DAQUI from Campus Medianeira of UTFPR and LAMAQ from Campus Curitiba/Ecoville for the equipments.

Additional information

Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES) -Finance Code 001.