Outdoor Weathering Performance

UV Protection
Solar radiation has a particularly harmful effect upon polymeric materials initiating degradation by causing superficial surface crazing. These crazes become sites for further erosion from water, dust, chemicals, etc. The degree to which these conditions affect the polymer depend largely upon environmental parameters such as geographical location, altitude, seasonal variations, etc.

Most Multiwall PC sheet has a one sided or two sided UV-protected surfaces, giving durability to outdoor weathering. This unique technology   helps to ensure long term optical quality under intensive UV exposure, and maintains the superior toughness of the polycarbonate material in comparison to other thermoplastic glazing.

Typical Values of UV protected Polycarbonate Sheet
Research into the long-term effects of weathering on glazing materials is basically focused upon measuring product performance through material property changes, typically mechanical strength, impact resistance, color retention, transparency etc.

A test was developed using high intensity xenon lamps to simulate natural sunlight. Together with other suitable UV filters and programmable rain cycles the test is able to simulate natural conditions.

    MJK Multiwall Systems encourages those interest to acquire a copy the National Greenhouse Manufacturers Association glazing standards ( www.ngma.com ). These standards outline guidelines for UV Testing.

Temperature Resistance
The heat build-up of glazing materials can be seen as a function of the absorption of the glazing material, in some case the pigments, and the solar intensity.

In countries with intense sun radiation, and when high energy absorbing tinted glazing is installed, heat build-up of the glazing can be considerable. Calculations and actual measurements on installed glass and pigmented plastics sheet in several projects throughout Europe have shown that sheet surface temperatures of 212°F can exist.

Multiwall PC and compact sheet is characterized by its retention of impact strength and stiffness at elevated temperatures, even over an extended period.

Multiwall PC sheet retains 85% of its room temperature flexural modulus at 176°F. The Vicat softening temperature and the Deflection Temperature Under Load are both around 284°F.

Multiwall PC & sheet has a continuous-use temperature of 212°F*. At the other end of the scale the minimum continuous- use temperature has been set at -40°F. Using polycarbonate sheet at lower temperatures is possible since the embrittlement temperature can be as low as -80°F.