Abstract：
The blend of butadiene and acrylonitrile copolymer (NBR) with natural poly-cis-isoprene (NR) shows increased resistance to swelling in solvents in comparison to the individual components. In aerospace, NBR rubber is used as thermal protection for rockets and shall not contain other polymers, even in low contents, otherwise, it can affect the protection performance and rocket safety by causing detachment of the elastomer/propellant interface; therefore, this investigation presents methodologies to determine the NR/NBR contents. This study explores different analytical techniques, such as Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, in the mid-infrared (MIR) by reflection and in the near-infrared by reflectance (NIRA) modes, Furthermore, quantification strategies by univariate, bivariate and multivariate (chemometric) models are evaluated and compared. A proposed methodology, based on multivariate Raman microscopy with partial least squares regression (PLS), showed high linearity (R2 > 0.99) and low error (< 0.82 %). The validation of FT-MIR data for the CH3, which presented lower error (1.3%) than vinylidene band (6%), showed that both methodologies (reflection and NIRA reflectance) can be used for the quantification of NR in NR/NBR. These results constitute a contribution to the state of the art in researching industrial and aerospace elastomeric applications.
摘要：
与单个组分相比,丁二烯和丙烯腈共聚物(NBR)与天然聚-顺式-异戊二烯(NR)的共混物显示出增加的在溶剂中的溶胀抗性。在航空航天领域,NBR橡胶用作火箭的热防护，不得含有其他聚合物。即使含量低，否则,它可以通过导致弹性体/推进剂界面的分离来影响防护性能和火箭安全性；因此，这项调查提出了确定NR/NBR含量的方法。本研究探讨了不同的分析技术，如拉曼光谱和傅里叶变换红外（FTIR）光谱，在中红外（MIR）反射和近红外（NIRA）反射模式，此外，单变量量化策略，评估和比较双变量和多变量（化学计量）模型。拟议的方法，基于多元拉曼显微镜和偏最小二乘回归(PLS)，表现出高线性(R2>0.99)和低误差(<0.82%)。对CH3的FT-MIR数据进行验证，其误差(1.3%)低于亚乙烯基带(6%)，结果表明，两种方法(反射和NIRA反射率)均可用于NR/NBR中NR的定量。这些结果对研究工业和航空航天弹性体应用的最新技术做出了贡献。
