Mahfuz Hassan, Hasan Mohammad, Dhanak Vinod, Beamson Graham, Stewart Justin, Rangari Vijaya, Wei Xin, Khabashesku Valery, Jeelani Shaik
Department of Ocean Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA.
Nanotechnology. 2008 Nov 5;19(44):445702. doi: 10.1088/0957-4484/19/44/445702. Epub 2008 Sep 30.
Pristine and functionalized silica (SiO(2)) nanoparticles were dispersed into nylon 6 and drawn into filaments through melt extrusion. The loading fraction of particles in both cases was 1.0 wt%. Fourier transform infrared (FTIR) studies revealed that reinforcement of pristine silica nanoparticles enhances the bond strength of each of the three basic bonds of nylon 6 namely, hydroxyl, amide, and carbonyl. As a result, the improvement over neat nylon in strength and modulus was 36% and 28% respectively, without any loss of fracture strain (80%). A silane coupling agent was then used through wet chemical treatment to functionalize silica nanoparticles. Functionalization induced an additional covalent Si-O-Si (siloxane) bond between silica particles and nylon backbone polymer while the enhancement in the basic bonds was retained. FTIR and x-ray photoelectron spectroscopy (XPS) studies confirmed the formation of the siloxane bond. This added chemical bond resulted in 76% and 55% improvement in tensile strength and modulus, and still retained 30% fracture strain. Calculation of the upper bound on Young's modulus indicates that one can reach within 5% of the bound with pristine silica particles, but it is exceeded by 15% when particles are functionalized.
将原始的和功能化的二氧化硅（SiO₂）纳米颗粒分散到尼龙6中，并通过熔融挤出制成细丝。两种情况下颗粒的负载分数均为1.0 wt%。傅里叶变换红外光谱（FTIR）研究表明，原始二氧化硅纳米颗粒的增强作用提高了尼龙6的三种基本键即羟基、酰胺基和羰基的键合强度。结果，与纯尼龙相比，强度和模量分别提高了36%和28%，而断裂应变没有损失（80%）。然后通过湿化学处理使用硅烷偶联剂对二氧化硅纳米颗粒进行功能化。功能化在二氧化硅颗粒和尼龙主链聚合物之间诱导形成了额外的共价Si-O-Si（硅氧烷）键，同时保留了基本键的增强效果。FTIR和X射线光电子能谱（XPS）研究证实了硅氧烷键的形成。这种额外的化学键使拉伸强度和模量分别提高了76%和55%，并且仍保留了30%的断裂应变。杨氏模量上限的计算表明，使用原始二氧化硅颗粒时可以达到上限的5%以内，但颗粒功能化时则超过上限15%。
