Multi-Catalyst ROMP System for Defect-Free Polymerization
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Solution Overview
Problem
Existing methods for controlling ring opening metathesis polymerization (ROMP) reactions, particularly with metal carbene olefin metathesis catalysts, fail to independently manage the time for reaching a hard polymer gel relative to the exotherm time, leading to defects in molded articles due to uneven polymerization and volatilization of liquid cyclic olefin monomers.
Innovation Solution
Employing a composition comprising at least two structurally and chemically distinct metal carbene olefin metathesis catalysts with a cyclic olefin resin and an optional exogenous inhibitor to form a ROMP composition, allowing for independent control over the time to reach a hard polymer gel before exotherm, thereby reducing defects in molded articles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single metal carbene olefin metathesis catalyst is used in ROMP composition, then the catalyst initiates polymerization rapidly, but the polymerization rate cannot be controlled independently from exotherm, leading to defects in molded articles
Solution Approach 1:
The patent divides the single catalyst system into multiple distinct metal carbene olefin metathesis catalysts (e.g., at least two different catalysts). Each catalyst contributes differently to the polymerization process, allowing the overall reaction to be segmented into controllable stages: initial polymerization rate control and subsequent exotherm management. This segmentation enables independent optimization of each stage without compromising the other.
2Loss of time
If the ROMP composition is introduced into the mold before complete catalyst dispersion, then the cycle time is reduced, but the polymerization becomes uneven across different regions of the mold
Solution Approach 1:
The patent employs a dynamic multi-catalyst system where different catalysts become active at different rates and stages of the polymerization process. This dynamic behavior allows the composition to maintain stability and uniformity even when introduced into the mold before complete catalyst dispersion. The faster-acting catalysts ensure immediate polymerization initiation, while slower-acting catalysts provide sustained reaction throughout the mold cavity, compensating for incomplete initial dispersion.
3Reliability
If the ROMP composition gels or exotherms before mold filling, then the polymerization control is improved, but the liquid cyclic olefin monomer volatilizes causing defects in the molded article
Solution Approach 1:
The patent implements preliminary action by designing a multi-catalyst system where the initial polymerization phase is carefully controlled to reach a hard polymer gel state before significant exotherm occurs. The catalyst composition is engineered to initiate polymerization at a controlled rate, allowing the monomer to convert to polymer gradually and form a gel network that prevents volatilization. Only after this preliminary gel formation does the exotherm phase begin, ensuring monomer stability throughout the process.
4Productivity
If various regions of the mold have different polymerization states, then the molding process is faster, but defects are generated due to liquid monomer volatilization during exotherm
Solution Approach 1:
The patent applies local quality by creating regions of different catalyst concentration or activity within the ROMP composition to match the spatial requirements of the mold. Areas prone to rapid exotherm receive catalyst formulations that promote gradual polymerization and early gel formation, while other regions are designed for faster polymerization. This localized optimization ensures that all regions of the mold achieve uniform polymerization states before exotherm, preventing volatilization-related defects while maintaining overall molding speed.
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
This approach ensures uniform polymerization across different regions of a mold, reducing voids and bubbles in the final product by controlling the polymerization process, leading to higher quality and defect-free polymer articles.
Implementation Method 1
metal carbene olefin metathesis catalysts
Implementation Method 2
catalyzing ring opening metathesis polymerization (ROMP) reactions
Implementation Method 3
the temperature generally begins to increase rapidly leading to a sharp exotherm
Data Source
AI summary
This invention relates to olefin metathesis catalysts and methods for controlling olefin metathesis reactions. More particularly, the present invention relates to methods and compositions for catalyzing and controlling ring opening metathesis polymerization (ROMP) reactions and the manufacture of polymer articles via ROMP. This invention also relates to olefin metathesis catalyst compositions comprising at least two metal carbene olefin metathesis catalysts, wherein the at least two metal carbene olefin metathesis catalysts are structurally different, are chemically different, are distinct compounds, are not isomers, are not structural isomers, are not diastereoisomers, are not stereoisomers, are not enantiomers, or are not cis/trans isomers of each other, or any combinations thereof. This invention also relates to a ROMP composition comprising a resin composition comprising at least one cyclic olefin, and an olefin metathesis catalyst composition comprising at least two metal carbene olefin metathesis catalysts, wherein the at least two metal carbene olefin metathesis catalysts are structurally different, are chemically different, are distinct compounds, are not isomers, are not structural isomers, are not diastereoisomers, are not stereoisomers, are not enantiomers, or are not cis/trans isomers of each other, or any combinations thereof. This invention also relates to a method of making an article comprising combining an olefin metathesis catalyst composition comprising at least two metal carbene olefin metathesis catalysts with a resin composition comprising at least one cyclic olefin, thereby forming a ROMP composition, and subjecting the ROMP composition to conditions effective to polymerize the ROMP composition, wherein the at least two metal carbene olefin metathesis catalysts are structurally different, are chemically different, are distinct compounds, are not isomers, are not structural isomers, are not diastereoisomers, are not stereoisomers, are not enantiomers, or are not cis/trans isomers of each other, or any combinations thereof. Polymer products produced via the metathesis reactions of the invention may be utilized for a wide range of materials and composite applications. The invention has utility in the fields of catalysis, organic synthesis, and polymer and materials chemistry and manufacture.