Absorbable Polymer Blends for Dimensional Stability
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Solution Overview
Problem
Conventional absorbable polymers used in medical devices face challenges in achieving rapid absorption and mechanical property loss while maintaining high initial strength and dimensional stability, particularly in tissues with varying healing rates, and existing manufacturing processes often result in inferior properties due to residual stresses and lack of crystallinity.
Innovation Solution
Development of novel absorbable polymer blends comprising a lactide-rich copolymer and poly(p-dioxanone) with specific molecular weight ratios and end-capping, which are processed to enhance crystallinity and reduce residual stresses, allowing for controlled absorption and mechanical property retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional absorbable polymers are used to achieve rapid absorption, then absorption rate is improved, but initial mechanical strength and dimensional stability deteriorate
Solution Approach 1:
The patent uses composite materials by blending poly(p-dioxanone) with lactide-rich copolymers to create a material that combines the rapid absorption properties of PDS with the mechanical strength and dimensional stability of the copolymer matrix. This composite approach allows simultaneous achievement of both rapid absorption and high initial strength
Solution Approach 2:
The patent applies parameter changes by controlling the molecular weight of poly(p-dioxanone) within specific ranges (weight average molecular weight of 10,000-100,000 Daltons) and optimizing the blend composition (1-50 weight percent PDS). These parameter optimizations enable tuning of both absorption rate and mechanical properties to achieve the desired balance
2Ease of manufacture
If conventional manufacturing processes are used, then ease of manufacture is improved, but dimensional stability and mechanical properties deteriorate due to residual stresses and lack of crystallinity
Solution Approach 1:
The patent applies preliminary action by incorporating nucleating agents into the polymer blend before manufacturing. These agents pre-establish crystallization sites that promote rapid and uniform crystallinity development during processing, thereby preventing residual stress formation and ensuring dimensional stability without requiring complex post-processing steps
Solution Approach 2:
The patent uses parameter changes by optimizing processing temperatures and cooling rates during manufacturing to facilitate crystallinity development. By controlling these thermal parameters in conjunction with the nucleating agents, the process achieves both ease of manufacture and superior dimensional stability
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 novel polymer blends provide medical devices with improved dimensional stability, rapid absorption, and high initial mechanical properties, addressing the limitations of conventional blends by optimizing molecular weight ratios and processing techniques.
Implementation Method 1
The chemistry of absorbable polymers is designed such that the polymers breakdown in vivo, for example by hydrolysis
Implementation Method 2
processed to enhance crystallinity and reduce residual stresses
Data Source
AI summary
Novel absorbable polymeric blends are disclosed. The blends have a first absorbable polymer type that is a polylactide polymer or a copolymer of lactide and glycolide and a second absorbable polymer type that is poly(p-dioxanone), wherein the first absorbable polymer type or the second absorbable polymer type or the first absorbable polymer type and the second absorbable polymer type additionally comprise a first polymeric component and a second polymeric component. The first polymeric component has a higher weight average molecular weight than the second polymeric component and at least one of said components is at least partially end-capped by a carboxylic acid. The novel polymeric blends are useful for manufacturing medical devices having dimensional stability, having engineered degradation and breaking strength retention in vivo. Also disclosed are novel absorbable medical devices made from these novel polymer blends, as well as novel methods of manufacture.