Semi-Aromatic Polyester Double Bond Control
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Solution Overview
Problem
Semi-aromatic polyesters are prone to thermal decomposition, leading to the formation of double bonds, carboxyl groups, and other structures that degrade the properties of polymerization products, making them unsuitable for further use.
Innovation Solution
A semi-aromatic polyester with a specific double bond content of 0.55-4.5 mmol/kg, preferably 0.70-2.5 mmol/kg, and most preferably 0.75-0.95 mmol/kg, is developed. This is achieved by using a repeating unit composed of aliphatic and aromatic dicarboxylic acids and diols, with precise control over the monomer ratios and reaction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If semi-aromatic polyester is used, then excellent machinability is achieved, but thermal decomposition occurs leading to property degradation
Solution Approach 1:
The invention changes the chemical composition parameters of the polyester by incorporating specific aliphatic diacids (adipic acid, decanedioic acid, dodecanedioic acid) in controlled ratios with aromatic diacids. This parameter adjustment modifies the polymer's thermal behavior to reduce decomposition and double bond formation while preserving machinability characteristics
Solution Approach 2:
The invention creates a composite polyester structure combining aliphatic and aromatic diacid components in specific ratios. This composite approach leverages the beneficial properties of both aliphatic (thermal stability) and aromatic (machinability) segments to achieve a balanced material with improved overall performance
2Quantity of substance
If semi-aromatic polyester undergoes thermal degradation, then double bonds and carboxyl groups are generated, but polymerization product properties worsen
Solution Approach 1:
The invention converts the harmful thermal degradation process into a beneficial outcome by carefully controlling the polymer composition. The specific aliphatic diacid content (40-80 mol%) acts as a thermal stabilizer that suppresses unwanted side reactions while allowing controlled formation of functional groups that can be utilized in further processing
Solution Approach 2:
The invention precisely controls the molar ratio parameters of diacids and diols, and the content of specific functional groups, to optimize the balance between thermal stability and reactivity. This parameter optimization ensures that thermal degradation produces beneficial functional groups rather than harmful byproducts
Data Source
AI summary
The present invention discloses a semi-aromatic polyester, and a preparation method therefor and an application thereof. The semi-aromatic polyester has a specific scope of double bond content. Compared with the existing semi-aromatic polyester, the semi-aromatic polyester of the present invention has better melting heat retention stability and fine color.