Crosslinked Polyester Shape Memory Compositions
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Solution Overview
Problem
Current biodegradable polyester materials lack shape memory properties, which are essential for applications requiring thermal stimuli-induced dimensional changes and biocompatibility in medical and non-medical contexts.
Innovation Solution
Development of crosslinked polyester compositions through polycondensation reactions involving saturated aliphatic diols, triols, and diacids, specifically incorporating glycerol, ethylene glycol, and sebacic acid, to create materials with shape memory properties and transition temperatures between 30°C and 100°C, combined with polytetrafluoroethylene (PTFE) for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If crosslinked polyesters are synthesized through polycondensation of diols, triols, and diacids, then shape memory properties are achieved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the molar ratios of diol to diacid (0.8-1.5) and triol to total polyol (0.2-0.8) to achieve desired shape memory transition temperatures (30-100°C). By adjusting these compositional parameters, the invention achieves shape memory properties while maintaining controllable manufacturing processes through defined ratio ranges.
Solution Approach 2:
The invention creates composite polyester structures by combining multiple monomer types (diols, triols, and diacids) in specific ratios to form crosslinked networks. This composite approach at the molecular level enables shape memory behavior while the standardized polycondensation process keeps manufacturing complexity manageable.
2Reliability
If transition temperature is adjusted to 30-100°C for medical applications, then biocompatibility is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines broad but controlled parameter ranges (diol:diacid 0.8-1.5, triol:polyol 0.2-0.8) that accommodate normal manufacturing variations while ensuring transition temperatures fall within the 30-100°C biocompatible range. This approach provides manufacturing tolerance without sacrificing biocompatibility reliability.
3Strength
If crosslink density is increased to enhance mechanical stability, then strength is improved, but degradation rate decreases
Solution Approach 1:
The invention controls the balance between crosslinking and degradation by limiting triol content to 0.2-0.8 of total polyol and maintaining diol:diacid ratios of 0.8-1.5. This creates moderate crosslink density that provides sufficient mechanical stability while preserving adequate degradation rates for medical applications through hydrolysis of ester bonds.
Solution Approach 2:
The patent creates local variations in crosslink density through the use of triol functional groups that introduce branching points within the polyester network. This results in heterogeneous structures with regions of varying crosslink density, providing both mechanical strength and degradation pathways.
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 resulting crosslinked polyester compositions exhibit shape memory behavior, biocompatibility, and bioabsorbability, enabling applications such as medical devices and non-medical uses where thermal stimuli can induce dimensional changes, while maintaining stability and safety.
Implementation Method 1
crosslinked polycondensation product of a polyol and at least one saturated linear aliphatic diacid or derivative thereof
Implementation Method 2
a shape memory polymer, the shape memory polymer exhibiting shape memory behavior
Implementation Method 3
the shape memory polymer exhibiting shape memory behavior upon heating to at least one transition temperature
Implementation Method 4
crosslinked polycondensation product
Data Source
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AI summary
A composite article has a macroscopic combination of a crosslinked polyester composition and at least one other material. The polyesters may be polycondensation reaction products of a diol, a triol and a diacid. Preferably, these polyesters are biocompatible, bioabsorbable, or exhibit shape memory behaviour with at least one transition temperature of greater than about 30°C and less than about 100°C and most preferably exhibit each of these qualities. The compositions may be adapted for a wide variety of uses, including medical applications.