UHMWPE Powder Pore Structure for Strength and Processing
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Solution Overview
Problem
Ultrahigh-molecular-weight polyethylene (UHMWPE) powders face challenges in achieving high strength and high drawing properties due to molecular chain disentanglement issues during kneading, leading to reduced strength and increased processing time, and there is a lack of discussion on appearance and processing ease in existing compositions.
Innovation Solution
A UHMWPE powder with a viscosity-average molecular weight between 10×10^4 and 1000×10^4, kneaded under specific conditions with liquid paraffin and antioxidants, having a controlled particle size distribution and pore structure to minimize molecular chain decomposition and enhance processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrahigh-molecular-weight polyethylene is kneaded in a state that is not sufficiently impregnated with solvent to shorten processing time, then productivity is improved, but the molecular chain is broken due to shear during kneading and strength is reduced
Solution Approach 1:
The patent applies preliminary action by pre-impregnating the ultrahigh-molecular-weight polyethylene powder with solvent before kneading. This preliminary impregnation disentangles the molecular chains in advance, allowing subsequent kneading to proceed quickly without breaking the molecular chains, thus resolving the contradiction between shortened processing time and maintained strength.
2Ease of operation
If ultrahigh-molecular-weight polyethylene powder with fine particles is used to improve flowability and processing ease, then ease of operation is improved, but the molecular chain becomes easily disentangled and strength is reduced
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution within a specific range (D50: 40-200 μm, D90/D10 ratio: 1.5-3.0) and adjusting the solvent content to 5-20 parts by mass per 100 parts by mass of powder. These parameter optimizations enable fine particles to maintain good flowability while preventing excessive molecular chain disentanglement, thus resolving the contradiction between ease of operation and strength.
3Strength
If sufficient solvent is used to fully impregnate the powder for complete molecular chain disentanglement, then strength is improved, but processing time increases and productivity decreases
Solution Approach 1:
The patent applies partial action by using a controlled amount of solvent (5-20 parts by mass per 100 parts by mass of powder) that is sufficient to achieve the necessary molecular chain disentanglement for strength, but not excessive to cause prolonged processing time. This optimized solvent dosage resolves the contradiction between adequate disentanglement and processing efficiency.
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 solution results in a UHMWPE powder that maintains high strength and drawing properties while improving processing ease and reducing the amount of lamp black, leading to stable production and enhanced physical properties of molded products.
Implementation Method 1
the ultrahigh-molecular-weight polyethylene powder having a particle size of 212 μm or larger has an average pore volume of 0.6 ml/g or larger and an average pore size of 0.3 μm or larger
Implementation Method 2
further 1 part by mass of an antioxidant per 100 parts by mass in total of the ultrahigh-molecular-weight polyethylene powder and the liquid paraffin
Data Source
AI summary
The ultrahigh-molecular-weight polyethylene powder of the present invention is an ultrahigh-molecular-weight polyethylene powder having a viscosity-average molecular weight Mv of 10×104 or higher and 1000×104 or lower, wherein viscosity-average molecular weight Mv(A) of a kneaded product obtained by kneading under specific kneading conditions, and the Mv satisfy the following relationship: “{Mv−Mv(A)}/Mv is 0.20 or less”, and the ultrahigh-molecular-weight polyethylene powder contains an ultrahigh-molecular-weight polyethylene powder having a particle size of 212 μm or larger, wherein the powder having a particle size of 212 μm or larger has an average pore volume of 0.6 ml/g or larger and an average pore size of 0.3 μm or larger.