The Effect of UV Degradation on HDPE Part Performance
Category
Sciences and Technology
Department
Plastics Engineering Technology
Student Status
Undergraduate
Research Advisor
Dr. Jeanne Norton
Document Type
Event
Location
Student Center Ballroom
Start Date
10-4-2025 2:00 PM
End Date
10-4-2025 4:00 PM
Description
Ultraviolet (UV) degradation poses a significant challenge when selecting plastics for exterior applications. UV radiation causes irreversible changes to polymers through chain scission, potentially reducing molecular weight and widening molecular weight distribution. Molecular-level chain scission results in plastic parts with visible defects and reduced performance. This study focused on gaining an understanding of the effect of outdoor weathering on plastic parts with different colorants. Virgin HDPE was injection molded into test bars without an added colorant (control). Three different colorants were added to HDPE and injection molded into test bars in the following amounts: Yellow, 0.75 wt%; Green, 2 wt%; and Black, 1 wt%. Subsequent to injection molding, samples were weathered in a QUV for 500 hours. After weathering, the weathered test bars were ground up, and the reduced, weathered material was again remolded into test bars. Characterization was performed on all samples (natural vs. color samples) under all conditions (no weathering, accelerated weathering, and remolded after accelerated weathering) to determine the degree of property degradation that had occurred. Mechanical properties were analyzed by tensile, flexural, and Izod impact testing. Thermal properties were analyzed by TGA and DSC. Physical properties were characterized by melt flow indexing, FT-IR spectroscopy, and colorimetry. Slight changes in mechanical, thermal, and physical properties were observed among color samples after weathering. More significant changes in properties were observed in HDPE samples without colorant. We demonstrated that weathering does alter properties, and the inclusion of colorant does reduce the impact of UV degradation on HDPE samples.
The Effect of UV Degradation on HDPE Part Performance
Student Center Ballroom
Ultraviolet (UV) degradation poses a significant challenge when selecting plastics for exterior applications. UV radiation causes irreversible changes to polymers through chain scission, potentially reducing molecular weight and widening molecular weight distribution. Molecular-level chain scission results in plastic parts with visible defects and reduced performance. This study focused on gaining an understanding of the effect of outdoor weathering on plastic parts with different colorants. Virgin HDPE was injection molded into test bars without an added colorant (control). Three different colorants were added to HDPE and injection molded into test bars in the following amounts: Yellow, 0.75 wt%; Green, 2 wt%; and Black, 1 wt%. Subsequent to injection molding, samples were weathered in a QUV for 500 hours. After weathering, the weathered test bars were ground up, and the reduced, weathered material was again remolded into test bars. Characterization was performed on all samples (natural vs. color samples) under all conditions (no weathering, accelerated weathering, and remolded after accelerated weathering) to determine the degree of property degradation that had occurred. Mechanical properties were analyzed by tensile, flexural, and Izod impact testing. Thermal properties were analyzed by TGA and DSC. Physical properties were characterized by melt flow indexing, FT-IR spectroscopy, and colorimetry. Slight changes in mechanical, thermal, and physical properties were observed among color samples after weathering. More significant changes in properties were observed in HDPE samples without colorant. We demonstrated that weathering does alter properties, and the inclusion of colorant does reduce the impact of UV degradation on HDPE samples.
