Low-Density Peroxide-Cured EPDM Insulation for Rocket Casings
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Solution Overview
Problem
Existing EPDM rubber insulations for rocket motor casings face challenges with sulphur curing, such as limited crosslink density, incompatibility with new generation propellants, and non-uniform mechanical properties, while peroxide curing introduces dispersion issues leading to discolouration and inhomogeneity.
Innovation Solution
A peroxide cured EPDM rubber insulation composition using precipitated silica as a filler, without fibrous fillers, ensures uniform dispersion of peroxide and maintains mechanical and thermal properties, suitable for large composite rocket motor casings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If peroxide curing is used to improve crosslink density and mechanical properties, then tensile strength and thermal stability are improved, but dispersion uniformity deteriorates leading to discolouration and inhomogeneity
Solution Approach 1:
Silane-modified EPDM rubber acts as an intermediary substance that facilitates uniform peroxide dispersion throughout the insulation composition. The silane modification creates compatibility between the polar peroxide and apolar EPDM matrix, preventing discolouration and inhomogeneity while maintaining high crosslink density and tensile strength
Solution Approach 2:
The invention changes the chemical parameters of the EPDM rubber by applying silane modification, which alters its polarity and reactivity. This parameter change enables better compatibility with peroxide curing agents, achieving uniform dispersion without sacrificing the improved mechanical properties that peroxide curing provides
2Ease of manufacture
If sulphur curing is used to achieve ease of manufacture, then processing is simplified, but crosslink density is limited and compatibility with new generation propellants deteriorates
Solution Approach 1:
The invention changes the curing mechanism from sulphur-based to peroxide-based curing, fundamentally altering the chemical parameters of the crosslinking process. This parameter change achieves both improved propellant compatibility and enhanced crosslink density, while the silane modification ensures the process remains manufacturable through uniform reaction
3Weight of moving object
If density is reduced to minimize inert weight, then weight of moving object is improved, but mechanical strength and thermal resistance may deteriorate
Solution Approach 1:
The invention creates a composite material system combining silane-modified EPDM rubber with peroxide curing agents and specific fillers. This composite approach achieves low density (0.95-1.05 g/cm³) while maintaining high mechanical strength through synergistic interactions between the modified polymer matrix and crosslinking network
Solution Approach 2:
By changing the crosslinking parameters through peroxide curing and silane modification, the invention achieves superior strength-to-density ratio. The modified curing system creates a more efficient crosslinking network that provides mechanical reinforcement without requiring increased material density
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves low density, high tensile strength, and thermal stability, with improved interfacial bonding and extended shelf life, suitable for various propellants, and meets the stringent requirements of large composite rocket motor casings.
Implementation Method 1
peroxide curing... capable of withstanding the high temperature gases and erosive particles produced while the propellant grain burns
Implementation Method 2
heat insulating layer or layers (insulation) protects the rocket motor casing from heat and erosion
Data Source
AI summary
The present invention relates to a low density peroxide cured EPDM rubber based insulation suitable for use in large composite rocket motor casing (CRMC), which uses only conventional filler. The said insulation can be used in large CRMC cast with all types of propellants viz., Composite based Solid Propellant, double base solid propellant, NEPE based new generation propellant etc. meeting insulation requirements of large CRMCs, improved thermal properties while retaining the required mechanical properties, having longer shelf life, higher thermal stability and excellent interfacial bonding strength with various interfaces. It also relates to a process for preparing peroxide cured EPDM rubber based insulation.