Study on the Improvement of Adhesion Strength between Composite Solid Propellant, Liner, and Heat‐Resistant Material

This study aims to improve the dispersion of Carbon Black (CB) filled Hydroxyl‐Terminated Polybutadiene (HTPB)‐Isophorone Diisocyanate (IPDI) based polyurethane liner by both adding a dispersant and developing a production process to obtain improved mechanical, rheological, thermal, and adhesion properties. Printex‐U (CB1) and Thermax N‐991 (CB2) carbon blacks were used as fillers. Three different dispersants, which are BYK 9076 (D1), BYK 9077 (D2), and BYK Silclean 3700 (D3) were added to the liner formulation at various amounts. BYK 9076 (D1) was found as the most effective dispersant due to its bifunctional chemical structure. By adding 2 wt.% of BYK 9076 (D1) dispersant to the polyurethane liner comprising 10 wt.% CB1, viscosity was reduced by 45 %, and tensile strength and elongation at break were improved from 1.77 MPa to 1.88 MPa and from 375 % to 385 % respectively. The dispersion of the CB in the polyurethane liner was further improved by the ultrasonication process and tensile strength and elongation at break were increased to 2.03 MPa and 425 %, respectively. This process also contributed to an improved Limiting oxygen index (LOI), elevating it from 20 % to 22 % initially and further by 25 % through ultrasonication. Scanning Electron Microscopy (SEM) verified that the addition of D1 dispersant and ultrasonication effectively reduced CB particle agglomeration. The migration of plasticizer was also assessed over 12 months through bonding testing, TGA, and FTIR analysis. It was noticed that the effective dispersion of CB particles made the liner more resistant to the plasticizer migration.

Section: Resultsmentioning

confidence: 99%

Enhancing the performance of HTPB‐IPDI‐based polyurethane composite liner through effective carbon black dispersion**

Aslan,

Atalar,

Atınç Yılmaz

et al. 2023

“…The liner has the most excellent adhesive strength when it is less hardened compared with when it is completely hardened. In addition, it is generally known that the lower the hardness of the liner, the higher is the adhesive strength [20, 21]. To achieve a strong adhesive strength after the adhesion is completed, it is more advantageous when the adhesive strength at the interface between the adhesive and the substrate molecules is greater than the cohesiveness between the adhesive's own molecules [3].…”

Section: Resultsmentioning

confidence: 99%

The Curing Reaction Rate of the Rocket Motor Liner Based on the Aging of a Curing System

Park

2021

In this study, the hardening reaction speed of a rocket motor liner based on the Aging of a curing system comprised of a hardener and hardening catalyst was investigated. With the increasing Aging time of the curing system, the liner viscosity build-up was accelerated. The raw material having the biggest impact on the hardening reaction of the curing system's liner was triphenylbismuth (TPB). Stirring isophorone diisocyanate and TPB form an ac-tivated complex, and the activated complex facilitates the urethane reaction. If TPB is ligand bound with isocyanate, it forms a TPB-isocyanate complex. This is a type of TPB's oxide, and the formation of the activated complex is visible through changes in its color. In addition, lining hardening time can be adjusted by the Aging period of the curing system through used in this study, and the adhesive strength with the liner and propellant can be improved.

“…The pot-life of a binder system is usually defined as the time interval that the viscosity increases to a specific value, for example, 20,000 mPa.s [86]. Highly-filled composite based on IPDI showed the highest crosslinking density (CLD) and modulus in comparison to other curing agents (HDI, TDI), retaining tensile strength and adequate elongation [87]. For long cure, aliphatic isocyanates are used, with less reactivity than aromatic ones.…”

Section: Curing Kinetics Of Htpb With Isocyanates and "Potlife"mentioning

confidence: 99%

Properties of Hydroxyl‐Terminal Polybutadiene (HTPB) and Its Use as a Liner and Binder for Composite Propellants: A Review of Recent Advances

Amado

Ross

Murakami

et al. 2022

This paper reviews hydroxyl-terminal polybutadiene (HTPB) used as liner and binder for composite propellants, applied in rocket motors studied throughout the last decades, emphasizing the recent advances. The contribution aims to show the importance of HTPB in the propellant composition and on the liner coating of the rocket motor, which is in contact with the propellant grain. This paper also shows that many researchers have thoroughly studied several properties of HTPB, which are rele-vant to its role in liners and propellants. We have also reviewed analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR) as a characterization technique for HTPB and HTPB-based polyurethanes. Reflection and transfectants FTIR may be a future trend in studies about polymeric matrices for liners and propellants, and in the area of propellant formulations that use energetic binders, graphene and nanomaterials.