Nitrocellulose Propellant with RDX and Surface Plasticizer

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Solution Overview

Problem

Existing propellant powders for military applications face challenges in achieving high energy density while maintaining low vulnerability to mechanical and thermal effects, particularly in warm climates and under extreme thermal loads, with previous LOVA propellant powders being costly, difficult to produce, and lacking reproducibility.

Innovation Solution

A single-base drive composed of nitrocellulose as the primary component, with a crystalline energy source based on RDX or HMX, and inert plasticizing additives, where the additives are homogeneously distributed within the matrix and concentrated near the surface to enhance mechanical resistance and thermal stability, allowing for high energy conversion efficiency and neutral temperature characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If LOVA propellant powders with crystalline explosives and inert/energetic binder are used to reduce vulnerability to mechanical influence, then resistance to mechanical impact improves, but production cost increases and manufacturing complexity increases

Engineering Contradiction:
Improvevulnerability to mechanical impactVSAvoidproduction cost and manufacturing difficulty
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by using nitrocellulose with specific nitrogen content (11-13.5% by weight) and controlling the content of crystalline energy source (1-25% by weight). This parameter optimization achieves low vulnerability while maintaining ease of production through conventional nitrocellulose processing methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite propellant system combining nitrocellulose binder with crystalline energy source (RDX or HMX) and inert plasticizing additives. This composite structure provides both mechanical impact resistance and chemical stability while being manufacturable through established processes.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If propellant powder energy density is increased for high performance potential, then energy conversion efficiency improves, but vulnerability to mechanical and thermal effects increases

Engineering Contradiction:
Improveenergy density and conversion efficiencyVSAvoidvulnerability to mechanical and thermal effects
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the nitrogen content of nitrocellulose (11-13.5% by weight) and controls the proportion of crystalline energy source (1-25% by weight) to achieve the right balance between energy density and stability. This parameter tuning allows high energy conversion (up to 44% thermal efficiency) while maintaining low vulnerability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies inert plasticizing additives with specific distribution patterns - concentrated near the surface zone with penetration depth of maximum 400 micrometers. This localized application enhances thermal stability and reduces vulnerability at critical surface areas while preserving bulk energy density.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If propellant powder chemical stability is improved for warm climate operations, then service life and cook-off temperature improve, but manufacturing complexity increases

Engineering Contradiction:
Improvechemical stability and service lifeVSAvoidmanufacturing process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent specifies nitrocellulose with controlled nitrogen content (11-13.5% by weight) and defines precise composition ranges for crystalline energy source (1-25%) and plasticizing additives. These parameter specifications achieve enhanced chemical stability for warm climate operations while maintaining compatibility with conventional manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses conventional, readily available materials (nitrocellulose, RDX/HMX, standard plasticizers) rather than exotic or specialized compounds. This approach achieves the required chemical stability without introducing complex or expensive manufacturing requirements.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Object-affected harmful factors

If inert plasticizing additives are concentrated near the surface zone to enhance mechanical resistance, then vulnerability to mechanical impact reduces, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemechanical impact resistanceVSAvoidadditive distribution control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent concentrates inert plasticizing additives in the surface zone with a defined penetration depth of maximum 400 micrometers. This local concentration provides enhanced mechanical impact resistance at the surface where it is most needed, while the simple depth specification (≤400 µm) keeps manufacturing control requirements manageable.

Inventive Principle:
Principle #3Local quality

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 solution provides improved resistance to mechanical stimuli, enhanced chemical stability, and high energy conversion efficiency, achieving up to 44% thermal efficiency in kinetic muzzle energy with stable performance across a wide temperature range, reducing vulnerability and production costs.

Implementation Method 1

single-base drive for accelerating projectiles, which is based on nitrocellulose

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

at least two inert plasticizing additives are provided, with at least a first inert plasticizing additive being present in a substantially homogeneously distributed manner in a matrix of the drive and a second inert plasticizing additive having an increased concentration limited to a penetration depth of a maximum of 400 micrometers in zones close to the surface

Methodology Applied
Scientific EffectPlasticization:

Data Source

PatentEP1857429B1Propulsive means for accelerating projectiles
Publication Date: 2013.03.27 NITROCHEM WIMMIS
  • EP1857429B1 patent drawingFigure 1~4

AI summary

The propellant for accelerating projectiles is nitrocellulose-based and contains a crystalline nitramine-based energy carrier and an inert plasticizing additive. The nitramine compound contains a structural element of the general chemical formula RN-NO2, where R is a residue. The nitramine compound is present in a concentration in the range of 1–35 wt%, particularly in the range of 5–25 wt%. The nitramine compound is preferably RDX. The inert plasticizing additive is a water-insoluble polyoxo compound, optionally in combination with a carboxyl-containing substance. A higher concentration may be provided in near-surface layers. The inert plasticizing additive is present in a concentration of 1–5 wt%.