Cellulose Cellulose Acetate Composite Filament Biodegradability
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Solution Overview
Problem
Current methods for producing biodegradable fibres, such as cellulose acetate, are insufficient in achieving consumer-acceptable degradation rates, with cellulose acetate fibres taking between one month and three years to biodegrade, and existing solutions have not provided a satisfactory commercial solution for rapid degradation.
Innovation Solution
The use of composite filaments spun from a dope comprising cellulose and cellulose acetate, dissolved in ionic liquids or N-methylmorpholine-N-oxide, which enhances biodegradability by disrupting crystallinity, and can include additional polymers and additives for improved functionality and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cellulose acetate fibres are used, then fibre strength and processability are improved, but biodegradability is insufficient (taking one month to three years to degrade)
Solution Approach 1:
The invention uses composite filaments combining cellulose and cellulose acetate in a single fibre structure. This allows the fibre to maintain the strength and processability of cellulose acetate while incorporating cellulose components that biodegrade more rapidly, achieving a balance between mechanical performance and biodegradability without requiring separate fibre layers or complex composite structures.
2Duration of action of moving object
If cellulose is used alone, then biodegradability is improved, but fibre strength and processability deteriorate
Solution Approach 1:
The composite filament structure integrates cellulose and cellulose acetate at the molecular level within the same fibre. The cellulose component provides rapid biodegradability while the cellulose acetate component maintains fibre strength and processability, creating a synergistic effect where the whole fibre performs better than either component alone.
3Ease of manufacture
If conventional spinning methods are used for cellulose acetate, then processability is improved, but compatibility with cellulose blending is poor (hydrolysis or solubility issues)
Solution Approach 1:
The invention employs a specific spinning process using a coagulation bath with controlled composition and temperature that acts as an intermediary medium. This process enables both cellulose and cellulose acetate to be spun together from the same dope without hydrolysis of cellulose acetate or solubility problems, as the coagulation conditions are optimized to accommodate both polymers simultaneously.
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 composite fibres exhibit significantly increased biodegradability compared to pure cellulose or cellulose acetate fibres, with accelerated degradation rates under both anaerobic and aerobic conditions, offering a versatile and comfortable fibrous product with enhanced biodegradability.
Implementation Method 1
by casting or spinning cellulose and cellulose acetate from an ionic liquid (IL) or from N-methylmorpholine-N-oxide (NMMO)
Implementation Method 2
the presence of acetate in the composite may disrupt the crystallinity of the cellulose, causing it to biodegrade more rapidly than cellulose itself
Implementation Method 3
the fibres biodegrade. Cellulose acetate fibres can take between one month and three years to biodegrade, dependant on environmental conditions
Data Source
Figure 1~4
AI summary
The present invention concerns a biodegradable fibre comprising composite filaments of cellulose and cellulose acetate, and a process for making such a fibre comprising providing a solution dope comprising a blend of cellulose and cellulose acetate in an ionic liquid or in N-methylmorpholine-N-oxide (NMMO), and spinning casting the blend into a protic solvent to generate fibres. The invention also concerns materials made from such a fibre, and garments or soft furnishings made from such a material.