Xenon lamp aging test simulates comprehensive factors such as light, temperature, humidity, and rainfall in natural climate conditions to conduct accelerated aging tests on materials to evaluate their weather resistance. The impact of this test on materials is extensive and profound, mainly reflected in physical properties, chemical structure, appearance, and functional characteristics. The following is a specific impact analysis:

1、 Physical performance changes

Decreased mechanical performance

Reduced tensile strength: Polymer materials (such as plastics and rubber) experience molecular chain breakage or cross-linking under xenon lamp irradiation, resulting in a decrease in tensile strength. For example, after 1000 hours of xenon lamp aging, the tensile strength of polycarbonate (PC) may decrease by 10% -20%.

Weakening of impact strength: The brittleness of the material increases, and the impact resistance performance deteriorates. For example, the impact strength of ABS material may decrease by more than 30% after aging.

Hardness change: Some materials (such as rubber) may experience hardness changes due to hardening or softening, which can affect their performance.

Change in thermal performance

Glass transition temperature (Tg) change: Polymer materials may experience an increase or decrease in Tg during aging due to changes in molecular structure, which can affect the stability of the material at high or low temperatures.

Heat distortion temperature (HDT) decrease: Materials are prone to deformation when heated, leading to a decrease in heat resistance.

Transparency and optical properties

Decreased transmittance: High transparency materials (such as PMMA, PC) have significantly reduced transmittance due to surface yellowing or internal structural changes. For example, after 500 hours of xenon lamp aging, the transmittance of PMMA may decrease from 93% to below 85%.

Increased haze: Surface roughness or internal microcracks of the material cause light scattering, resulting in an increase in haze and affecting transparency.

Refractive index variation: The refractive index of optical materials (such as lenses) may change due to aging, affecting imaging quality.

2、 Chemical structural changes

Molecular chain breakage and cross-linking

Photooxidation reaction: Ultraviolet (UV) radiation triggers the breakage of material molecular chains, generating free radicals, which further trigger oxidation reactions and lead to the deterioration of material properties.

Crosslinking reaction: Some materials (such as rubber) may undergo cross-linking during the aging process, causing the material to become hard and brittle.

Degradation of additives

Antioxidant consumption: Antioxidants in materials are consumed during the aging process, losing their inhibitory effect on oxidation and accelerating material aging.

UV absorber failure: UV absorbers (such as UV-327) may undergo photodegradation after absorbing ultraviolet light, resulting in a decrease in protective effect.

Plasticizer migration: Plasticizers migrate from the interior of the material to the surface, causing the material to become hard and brittle, and may also contaminate the contact environment.

Surface chemical changes

Formation of oxide layer: The material surface generates an oxide layer due to oxidation reactions, which may alter surface properties such as hydrophilicity and adhesion.

Surface pollution: During the aging process, the material surface may adsorb pollutants from the environment (such as dust, grease), affecting its appearance and performance.

3、 Appearance changes

color change

Yellowing: Polymer materials turn yellow due to the generation of chromophores through photooxidation reactions. For example, after xenon lamp aging, the yellowing index (YI) of polyethylene (PE) may significantly increase.

Fading: Dyes or pigments undergo photodegradation under light, resulting in a lighter or faded color of the material.

Increased color difference (Δ E): By measuring with a colorimeter, the color difference of the material before and after aging may exceed the allowable range of industry standards (such as Δ E>3).

surface defect

Cracks and fissures: Microcracks are generated on the surface of materials due to stress concentration or chemical degradation, which further propagate into fissures.

Powdering: The material surface forms a powdery substance due to the breakage of molecular chains, which is prone to detachment and pollutes the environment.

Bubbling and delamination: Multi layer materials (such as coatings and composite materials) may experience foaming or delamination due to decreased interfacial adhesion.

Glossiness variation

Decreased glossiness: The surface roughness or formation of oxide layer on the material leads to a decrease in glossiness, which affects the aesthetic appearance.

4、 Degradation of functional characteristics

Changes in electrical performance

Reduced insulation resistance: Polymer insulation materials (such as PVC, PE) have decreased insulation performance after aging, which may cause leakage or short circuit risks.

Changes in dielectric constant: Changes in material polarization characteristics that affect its performance in electronic devices.

Decreased corrosion resistance

Aging of metal coatings: Coating materials (such as epoxy resins) increase porosity due to aging, making the metal substrate susceptible to corrosion.

Enhanced hygroscopicity of polymer materials: After aging, the hygroscopicity of the material increases, which may trigger hydrolysis reactions and further reduce performance.

Biocompatibility changes

Medical device materials: After aging, materials may release toxic substances (such as plasticizers, degradation products) that affect biocompatibility and need to be verified through biosafety testing.

5、 Typical effects of different material types

Material TypeTypical impact

Plastic (such as PC, PMMA)Decreased transmittance, yellowing, embrittlement, and decreased impact strength

Rubber (such as SBR, NBR)Hardening, embrittlement, decreased tensile strength, and increased compression deformation

Coatings (such as acrylic, polyurethane)Reduced glossiness, powdering, decreased adhesion, and color fading

Textiles (such as polyester, nylon)Decreased intensity, faded color, and hardened hand feel

Metal (such as coated steel)Coating blistering, delamination, and corrosion of metal substrates

6、 The significance of testing and corresponding measures

Test significance

Quality control: By simulating aging, material defects can be detected in advance to avoid product failure after launch.

Life prediction: Based on accelerated aging data, calculate the actual life of the material in use (such as 10 years of outdoor exposure equivalent to 5000 hours of xenon lamp aging).

Cost optimization: Reduce outdoor testing cycles (usually 1-2 years) and lower research and development costs.

countermeasures

Material modification: add anti-aging additives (such as ultraviolet absorber, light stabilizer, antioxidant).

Surface treatment: Apply UV resistant coating or perform surface modification (such as plasma treatment).

Structural design optimization: reduce the exposed area of materials or increase protective layers (such as sunshades, coatings).