CTFE-VC Copolymers for High Glass Transition Temperature
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Solution Overview
Problem
Prior processes for producing chlorotrifluoroethylene/vinyl chloride copolymers result in materials with molecular weights below 70,000 and glass transition temperatures of 33°C - 34°C, limiting their applications due to insufficient mechanical properties and processability.
Innovation Solution
Development of copolymers and terpolymers with higher molecular weights and glass transition temperatures (70°C to 87°C) by optimizing the polymerization process to achieve weight average molecular weights from 100,000 to 300,000 and surface energies between 30 to 40 mJ/m², using a process that involves an initial aqueous reaction medium with a CTFE:VC weight ratio of 50:50 to 5:95 and conducting the reaction at temperatures between 20°C to 50°C for at least 15 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If prior polymerization processes are used to produce VC/CTFE copolymers, then the copolymers can be manufactured, but the molecular weight remains below 70,000 and glass transition temperature is only 33°C - 34°C, resulting in insufficient mechanical properties
Solution Approach 1:
The patent applies parameter changes by modifying polymerization conditions including using specific initiators (peroxymonosulfate, azobisisobutyronitrile, 2,2'-azobis(2-methylpropionamidine) dihydrochloride), controlling reaction temperature (20°C to 50°C), adjusting monomer ratios (VC:CTFE from 95:5 to 50:50 by weight), and extending reaction time (at least 15 hours) to achieve copolymers with molecular weights of 100,000 to 300,000 and glass transition temperatures of 70°C to 87°C, thereby resolving the contradiction between mechanical properties and processability
2Manufacturing precision
If vinyl chloride is added in a step-wise manner to maintain monomer ratio, then the copolymer composition can be controlled, but the process complexity increases with multiple addition stages
Solution Approach 1:
The patent applies preliminary action by pre-calculating and charging the exact amounts of vinyl chloride and chlorotrifluoroethylene monomers at the beginning of polymerization based on desired copolymer composition. This eliminates the need for multiple step-wise additions during reaction, reducing process complexity while maintaining precise composition control through initial stoichiometric preparation
3Reliability
If polyvinyl chloride is used to provide chemical stability, then good chemical stability is achieved, but the material becomes brittle and requires plasticizers for flexibility
Solution Approach 1:
The patent applies composite materials by creating copolymers that combine vinyl chloride units (providing chemical stability) with chlorotrifluoroethylene units (providing flexibility and lower glass transition temperature). This copolymerization produces a single-phase material with inherent flexibility without requiring external plasticizers, resolving the contradiction between chemical stability and flexibility through molecular-level composition control
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 copolymers and terpolymers exhibit improved mechanical properties, solubility, hydrophilicity, and adhesion, enabling their use in membranes, coatings, and other applications such as reverse osmosis, nanofiltration, and selective gas separation with enhanced performance.
Implementation Method 1
reacting said chlorotrifluoroethylene monomers and vinyl chloride monomers under conditions to produce a copolymer
Data Source
AI summary
Disclosed are copolymers and terpolymers chlorotrifluoroethylene and vinyl chloride having improved properties, and particularly a high glass transition temperature, for use in membranes, coatings, barrier films, and other applications and process for forming such copolymers and terpolymers, which are useful in reverse osmosis desalination, nanofiltration, ultrafiltration, microfiltration, membrane distillation, pervaporation, selective gas separation, batteries and fuel cells.