This article addresses the effect of enhanced segmental mixing on various physical properties of ferrocenylsilane tethered polybutadiene based polyurethane (PU). To study this, 2-(ferrocenylpropyl) dimethylsilane (FPDS) has been grafted to the pendant vinyl double bond of hydroxyl terminated polybutadiene (HTPB) and 2, 4-dinitrobenzene attached HTPB (HTPB-DNB) through hydrosilylation reaction and then this resulting diols (FPDS-g-HTPB and FPDS-g-HTPB-DNB) were polymerized with isophorone diisocyanate (IPDI) to obtain FPDS-g-HTPB-PU and FPDS-g-HTPB-DNB-PU. Spectral (NMR, IR) analysis, molecular weight measurements and estimation of free hydroxyl contents were carried out to confirm the formation of these new diols. The careful variation of the grafting condition altered the extent of FPDS tethering on the diols which resulted varying amount of Si and Fe contents in these modified HTPBs. Density functional theory (DFT) calculation revealed the presence of various interactions of Si with various functionalities including ferrocene of the chain which resulted highly cross-linked polymer matrix. Cyclic voltammetry (CV) measurements of FPDS-g-HTPB-DNB displayed non-Nerstain reversible redox system with slow electron transfer process owing to the presence of DNB. Further, the PUs obtained from these HTPBs were prepared and characterized thoroughly in terms of thermal, mechanical, structural and tensile properties to study the segmental mixing between hard and soft segments of PUs owing to the presence of Si, Fe and DNB in the PU chain. Higher degree of segmental mixing was noticed when Si, Fe in the diol increased and also presence of DNB in the diol played a significant role in inducing the segmental mixing. The co-existence of segmental mixing and phase separation has been confirmed by small-angle x-ray scattering studies which further reaffirmed by FESEM analysis. Finally, composite solid propellants (CSPs) were prepared from these modified HTPBs and burn rate measurements were carried out. We found that CSPs obtained from FPDS-g-HTPB-DNB displayed ~10% higher burn rate than the CSP made from bare HTPB-DNB.

本文讨论了增强的分段混合对二茂铁基硅烷拴系的聚丁二烯基聚氨酯（PU）的各种物理性能的影响。为了对此进行研究，已通过氢化硅烷化反应将2-（二茂铁基丙基）二甲基硅烷（FPDS）接枝到了羟基封端的聚丁二烯（HTPB）和2，4-二硝基苯连接的HTPB（HTPB-DNB）的侧链乙烯基双键上，然后将所得二醇（FPDS- g -HTPB和FPDS - g -HTPB-DNB）与异佛尔酮二异氰酸酯（IPDI）聚合得到FPDS- g -HTPB-PU和FPDS- g-HTPB-DNB-PU。进行了光谱（NMR，IR）分析，分子量测量和游离羟基含量的估计以确认这些新二醇的形成。接枝条件的仔细变化改变了二醇上FPDS的束缚程度，导致这些改性HTPBs中Si和Fe含量的变化。密度泛函理论（DFT）计算表明，硅与各种官能团（包括链的二茂铁）之间存在各种相互作用，从而导致高度交联的聚合物基体。FPDS- g的循环伏安法（CV）测量-HTPB-DNB由于存在DNB，显示出非神经元可逆氧化还原系统，且电子转移过程缓慢。此外，制备了从这些HTPB获得的PU，并在热，机械，结构和拉伸性能方面进行了全面表征，以研究由于PU链中存在Si，Fe和DNB而导致PU的硬链段与软链段之间的链段混合。当二醇中的Si，Fe增加并且二醇中DNB的存在在诱导分段混合中起重要作用时，注意到较高的分段混合度。分段混合和相分离的共存已经通过小角度X射线散射研究得到了证实，而FESEM分析进一步证实了这一点。最后，由这些改性的HTPB制备复合固体推进剂（CSP），并进行燃烧速率测量。我们发现从FPDS获得的CSP-g -HTPB-DNB的燃烧速率比裸HTPB-DNB的CSP高约10％。