Mechanical properties and gradient variations of polymers under ultraviolet radiation

2007 ◽  
Vol 106 (5) ◽  
pp. 3253-3258 ◽  
Author(s):  
Xue Feng Yao ◽  
Dong Liang Liu ◽  
Heisen Yang Yeh
Keyword(s):  
Mechanical Properties ◽  
Ultraviolet Radiation

scholarly journals The Effects of Weathering on Mechanical Properties of Glass Fiber Reinforced Plastics (Grp) Materials

1970 ◽  
Vol 1 (2) ◽  
Author(s):  
H. Abdullah ◽  
S. Al Araimi and R. A. Siddiqui
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Ultraviolet Radiation ◽  
Glass Fiber ◽  
Exposure Time ◽  
Atmospheric Conditions ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Plastics

Glass fiber reinforced plastics composite is extensively used as a structural material for pools, oil pipes and tanks because it has good corrosion resistance properties.  The effects of weathering on the mechanical properties of glass fiber reinforced plastics (GRP) in the Sultanate of Oman have been studied.  The tensile and three point bend specimens were exposed to outdoor conditions (open atmosphere) in sunlight and tested for various intervals of time.  It was observed that as the exposure time to sunlight, ultraviolet radiation and dust increases the mechanical properties of GRP materials decrease.  The effects of relative humidity (%RH) on the mechanical properties were also studied. It was found that as the relative humidity increased in the atmosphere during the exposure time, the tensile strength, flexural strength and modulus of elasticity are lowered. This work has revealed that the decrease in the mechanical properties of GRP under weathering conditions is subjected to atmospheric conditions such as humidity, temperature, ultraviolet radiation and pollutant.Key Words: Weathering, Glass-Fiber Reinforced Plastics, Degradation

Ultraviolet Radiation Affects Thoratec HeartMate II Driveline Mechanical Properties

ASAIO Journal ◽  
2015 ◽  
Vol 61 (6) ◽  
pp. 731-733 ◽  
Author(s):  
Annicka C. Evans ◽  
G. Andrew Wright ◽  
Sean P. McCandless ◽  
Sandi Stoker ◽  
Dylan Miller ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultraviolet Radiation ◽  
Heartmate Ii

scholarly journals Influence of Ultraviolet Radiation on Mechanical Properties of a Photoinitiator Compounded High Vinyl Styrene–Butadiene–Styrene Block Copolymer

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1287
Author(s):  
Sanjoy Datta ◽  
Radek Stocek ◽  
Kinsuk Naskar
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Ultraviolet Radiation ◽  
Thermoplastic Elastomer ◽  
Labile Hydrogen ◽  
Hydrogen Atoms ◽  
Time Saving ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Ultraviolet curing of elastomers is a special curing technique that has gained importance over the conventional chemical crosslinking method, because the former process is faster, and thus, time-saving. Usually, a suitable photoinitiator is required to initiate the process. Ultraviolet radiation of required frequency and intensity excites the photoinitiator which abstracts labile hydrogen atoms from the polymer with the generation of free radicals. These radicals result in crosslinking of elastomers via radical–radical coupling. In the process, some photodegradation may also take place. In the present work, a high vinyl (~50%) styrene–butadiene–styrene (SBS) block copolymer which is a thermoplastic elastomer was used as the base polymer. An attempt was made to see the effect of ultraviolet radiation on the mechanical properties of the block copolymer. The process variables were time of exposure and photoinitiator concentration. Mechanical properties like tensile strength, elongation at break, modulus at different elongations and hardness of the irradiated samples were studied and compared with those of unirradiated ones. In this S-B-S block copolymer, a relatively low exposure time and low photoinitiator concentration were effective in obtaining optimized mechanical properties. Infrared spectroscopy, contact angle and scanning electron microscopy were used to characterize the results obtained from mechanical measurements.

scholarly journals Effect of PCE on Properties of MMA-Based Repair Material for Concrete

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 859
Author(s):  
Jian Han ◽  
Lingling Xu ◽  
Tao Feng ◽  
Xin Shi ◽  
Pan Zhang
Keyword(s):  
Mechanical Properties ◽  
Ultraviolet Radiation ◽  
Methyl Methacrylate ◽  
Mass Fraction ◽  
Bending Strength ◽  
Polymerization Reaction ◽  
Repair Material ◽  
Ionic Solutions ◽  
Low Viscosity ◽  
Repair Materials

Methyl methacrylate (MMA)-based repair material for concrete has the characteristics of low viscosity, excellent mechanical properties, and good durability. However, its application is limited due to its large shrinkage. Existing studies have shown that adding perchloroethylene can reduce the shrinkage. On this basis, other properties of modified MMA-based repair materials were tested and analyzed in the present study. The results revealed that the addition of perchloroethylene (PCE) can hinder the polymerization reaction of the system. When CaCO3 with a mass fraction of 30% was added, the viscosity of the material was within the range of 450–500 mPa·s, and the shrinkage decreased to approximately 10%. The bending strength of MMA, and MMA modified by PCE, repair materials at 28 days could reach up to 28.38 MPa and 29.15 MPa, respectively. After the addition of HS-770 light stabilizer with a mass fraction of 0.4%, the retention ratios of the bending strength of materials with ratios of P0 and P3 could reach 91.11% and 89.94%, respectively, after 1440 h of ultraviolet radiation. The retention ratio of the bending strength of the material could reach more than 95% after immersion in different ionic solutions for 90 days.

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