UV-Resistant Elastomer Composites for Sterilizable PPE

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Solution Overview

Problem

Existing personal protective equipment (PPE), such as N95 masks, face degradation when exposed to ultraviolet germicidal irradiation (UVGI), compromising their fit and filtration efficacy, and contribute to significant waste generation, necessitating the development of UV-resistant elastomers for sterilization and reuse.

Innovation Solution

A composite material comprising a polyurethane elastomeric matrix with solution-exfoliated graphene and ethyl cellulose (EC) as UV-resistant additives, which absorbs UV light, suppresses degradation, and provides mechanical reinforcement, enabling the composite to remain robust through at least 150 sterilization cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UVGI is used for sterilization of N95 masks, then microbial nucleic acids are effectively disinfecting the mask filters, but the elastomeric head straps degrade compromising fit and filtration efficacy

Engineering Contradiction:

Improvesterilization efficacyVSAvoidelastomeric strap integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent develops a composite elastomeric material incorporating UV-resistant additives (such as hindered amine light stabilizers and UV absorbers) into the polyisoprene matrix. This composite structure allows the material to maintain its elastomeric properties while gaining resistance to UVGI-induced degradation, enabling both effective sterilization and strap integrity preservation

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces UV-resistant chemical additives as intermediaries between the UVGI radiation and the elastomeric strap material. These additives (HALS and UV absorbers) act as mediators that absorb or neutralize the harmful UV-C radiation before it can degrade the polyisoprene chains, thereby protecting the strap while allowing sterilization to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If single-use PPE is disposed of monthly, then viral transmission risk is reduced, but environmental waste generation increases significantly

Engineering Contradiction:

Improveviral transmission riskVSAvoidPPE waste generation

Core Design Contradiction:

Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent enables the recovery and reuse of PPE materials by providing UV-resistant elastomeric compositions that can withstand repeated sterilization cycles. This allows PPE items like mask straps and glove components to be discarded less frequently and recovered for continued use, reducing waste while maintaining safety

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent fundamentally changes the durability parameter of elastomeric materials by incorporating UV-resistant additives. This parameter change extends the service life of PPE components from single-use to multiple-use, allowing them to withstand repeated UVGI sterilization cycles without degradation, thereby reducing disposal frequency and waste generation

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If N95 masks are stockpiled for future pandemics, then preparedness is improved, but aging of straps and seals influences fit and effectiveness

Engineering Contradiction:

Improvepandemic preparednessVSAvoidmask fit and effectiveness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary protective action by incorporating UV-resistant additives into the elastomeric material during manufacturing. This preliminary stabilization prevents degradation during long-term storage and stockpiling, ensuring that masks remain effective when needed for future pandemics

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies the chemical composition parameter of the elastomeric material by adding UV stabilizers and absorbers. This parameter change increases the material's resistance to oxidative degradation and UV damage, extending the shelf life of stockpiled masks while maintaining fit and filtration effectiveness

Inventive Principle:

Principle #35Parameter changes

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 graphene-polyurethane composite maintains mechanical properties and UV resistance, allowing for safe reuse of PPE and reducing waste by extending the life cycle of elastomeric materials in PPE and other applications.

Implementation Method 1

the UV-resistant additive is adapted for absorbing UV light, thereby suppressing UV-induced degradation of the elastomeric matrix

Methodology Applied

Scientific EffectUV light absorption: Absorption (EM radiation)

Data Source

PatentUS20240052134A1Sterilizable and reusable ultraviolet-resistant elastomer composites, fabricating methods, and applications of same

Publication Date: 2024.02.15 NORTHWESTERN UNIV

AI summary

The invention relates to a sterilizable and reusable ultraviolet-resistant elastomer composites including an elastomeric matrix comprising at least one elastomer; and an UV-resistant additive incorporated into the elastomeric matrix. The ultraviolet-resistant elastomer composite remains mechanically robust over at least 150 sterilization cycles, enabling safe reuse following ultraviolet germicidal irradiation (UVGI). Beyond N95 masks, these UVGI-compatible ultraviolet-resistant elastomer composites have potential utility in other PPE applications to address the broader issue of single-use waste.