Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
Biomacromolecules. 2013 Mar 11;14(3):900-9. doi: 10.1021/bm301995s. Epub 2013 Feb 27.
This study investigates the efficacy of two-dimensional (2D) carbon and inorganic nanostructures as reinforcing agents for cross-linked composites of the biodegradable and biocompatible polymer polypropylene fumarate (PPF) as a function of nanostructure concentration. PPF composites were reinforced using various 2D nanostructures: single- and multiwalled graphene oxide nanoribbons (SWGONRs, MWGONRs), graphene oxide nanoplatelets (GONPs), and molybdenum disulfide nanoplatelets (MSNPs) at 0.01-0.2 weight% concentrations. Cross-linked PPF was used as the baseline control, and PPF composites reinforced with single- or multiwalled carbon nanotubes (SWCNTs, MWCNTs) were used as positive controls. Compression and flexural testing show a significant enhancement (i.e., compressive modulus = 35-108%, compressive yield strength = 26-93%, flexural modulus = 15-53%, and flexural yield strength = 101-262% greater than the baseline control) in the mechanical properties of the 2D-reinforced PPF nanocomposites. MSNP nanocomposites consistently showed the highest values among the experimental or control groups in all the mechanical measurements. In general, the inorganic nanoparticle MSNP showed a better or equivalent mechanical reinforcement compared to carbon nanomaterials, and 2D nanostructures (GONPs, MSNPs) are better reinforcing agents compared to one-dimensional (1D) nanostructures (e.g., SWCNTs). The results also indicated that the extent of mechanical reinforcement is closely dependent on the nanostructure morphology and follows the trend nanoplatelets > nanoribbons > nanotubes. Transmission electron microscopy of the cross-linked nanocomposites indicated good dispersion of nanomaterials in the polymer matrix without the use of a surfactant. The sol-fraction analysis showed significant changes in the polymer cross-linking in the presence of MSNP (0.01-0.2 wt %) and higher loading concentrations of GONP and MWGONR (0.1-0.2 wt %). The analysis of surface area and aspect ratio of the nanostructures taken together with the above results indicated differences in nanostructure architecture (2D vs 1D nanostructures), and the chemical compositions (inorganic vs carbon nanostructures), number of functional groups, and structural defects for the 2D nanostructures may be key properties that affect the mechanical properties of 2D nanostructure-reinforced PPF nanocomposites and the reason for the enhanced mechanical properties compared to the controls.
本研究调查了二维（2D）碳和无机纳米结构作为可生物降解和生物相容的聚富马酸丙烯酯（PPF）交联复合材料的增强剂的功效，其功能取决于纳米结构的浓度。使用各种 2D 纳米结构：单壁和多壁氧化石墨烯纳米带（SWGONRs、MWGONRs）、氧化石墨烯纳米片（GONPs）和二硫化钼纳米片（MSNPs），以 0.01-0.2 重量%的浓度增强 PPF 复合材料。交联的 PPF 用作基准对照，并用单壁或多壁碳纳米管（SWCNTs、MWCNTs）增强的 PPF 复合材料用作阳性对照。压缩和弯曲测试显示，2D 增强的 PPF 纳米复合材料的机械性能有显著提高（即，压缩模量=35-108%，压缩屈服强度=26-93%，弯曲模量=15-53%，弯曲屈服强度=101-262%，高于基准对照）。在所有机械测量中，MSNP 纳米复合材料在实验或对照组中始终表现出最高值。一般来说，与碳纳米材料相比，无机纳米颗粒 MSNP 显示出更好或同等的机械增强效果，与一维（1D）纳米结构（例如，SWCNTs）相比，二维（2D）纳米结构（例如，GONPs、MSNPs）是更好的增强剂。结果还表明，机械增强的程度与纳米结构形态密切相关，遵循纳米片>纳米带>纳米管的趋势。交联纳米复合材料的透射电子显微镜表明，在没有使用表面活性剂的情况下，纳米材料在聚合物基质中具有良好的分散性。溶胶分数分析表明，在存在 MSNP（0.01-0.2wt%）和更高负载浓度的 GONP 和 MWGONR（0.1-0.2wt%）的情况下，聚合物交联发生了显著变化。将纳米结构的比表面积和纵横比分析与上述结果结合起来，表明纳米结构的建筑结构（二维与一维纳米结构）和化学成分（无机与碳纳米结构）存在差异，2D 纳米结构的官能团数量和结构缺陷可能是影响 2D 纳米结构增强 PPF 纳米复合材料机械性能的关键特性，也是与对照相比增强机械性能的原因。
