Partially Aromatic Copolyamide Moulding Compound Thermal Stability
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Solution Overview
Problem
Conventional polyamide moulding compounds, especially those based on partially aromatic polyamides, face challenges with inadequate thermal aging resistance, poor processing properties, and low impact resistance and elongation at break, making them unsuitable for high-temperature applications such as the engine compartment of automobiles.
Innovation Solution
A moulding composition comprising 60 to 99 parts by weight of a partially aromatic copolyamide with specific monomer units and 40 to 1 parts by weight of an olefinic copolymer, including ethene-based monomer units, a 1-alkene, and an aliphatically unsaturated dicarboxylic acid anhydride, which enhances thermal stability and mechanical properties like impact resistance and elongation at break.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If partially aromatic copolyamides with high melting points are used, then thermal stability and melting point are improved, but processability deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyamide by incorporating specific ratios of aromatic and aliphatic monomers (30-70 mol% aromatic content), and adjusts the impact modifier composition with specific grafting levels (0.5-5 wt% anhydride groups), thereby achieving optimal balance between high melting point and processability
Solution Approach 2:
The patent creates a composite material system combining partially aromatic copolyamide matrix with polyolefinic impact modifier containing grafted anhydride groups, where the composite achieves both high thermal stability and improved processability through the synergistic interaction between matrix and modifier phases
2Strength
If impact modifiers are added to improve toughness, then impact resistance and elongation at break are improved, but thermal aging resistance deteriorates
Solution Approach 1:
The patent optimizes the chemical parameters of the impact modifier by controlling the anhydride grafting content (0.5-5 wt%) and the ratio of polyolefin to anhydride groups, thereby achieving sufficient impact modification while maintaining thermal aging resistance through balanced composition
Solution Approach 2:
The patent uses anhydride-grafted polyolefin as an intermediary substance that bridges the matrix and dispersed rubber phases, providing both impact modification and thermal stability through the reactive anhydride groups that form bonds with the polyamide matrix while the polyolefin backbone maintains thermal resistance
3Stability of the object's composition
If conventional impact modifiers are used, then elongation at break is improved, but processing properties deteriorate
Solution Approach 1:
The patent adjusts the molecular weight, grafting density, and anhydride content parameters of the impact modifier to achieve optimal balance between elongation enhancement and processing flow characteristics
Solution Approach 2:
The patent creates local quality differentiation by concentrating the reactive anhydride groups at the interface between matrix and dispersed phase, while the bulk polyolefin maintains good processability, thereby achieving localized reinforcement without compromising overall processing properties
Data Source
AI summary
A moulding composition contains at least 40 wt % of components a) and b). Based on the sum of components a) and b), there are 60-99 wt % of component a) and 40-1 wt % of component b). Component a) is a partially aromatic copolyamide containing, as polymerized monomer units, 30-90 mol % of a combination of hexamethylenediamine and terephthalic acid and 70-10 mol % of a combination of hexamethylenediamine and a linear aliphatic dicarboxylic acid having 8-19 C atoms. Component b) is an olefinic copolymer containing, as polymerized monomer units, i) 35-94.9 wt % of ethene-based monomer units, ii) 5-65 wt % of monomer units based on a 1-alkene having 4-8 C atoms, iii) 0-10 wt % of monomer units based on an olefin different from i) and ii), and iv) 0.1-2.5 wt % of monomer units based on an aliphatically unsaturated dicarboxylic acid anhydride, where the sum of wt % of i), ii), iii) and iv) is 100%.