The lamp diffuser of our garden lighting is polycarbonate(PC)
Dec 12, 2018


pc-1


What is PC and what is it used for?

Polycarbonate (PC) plastics are a naturally transparent amorphous thermoplastic.PC is commonly used for plastic lenses in eyewear, in medical devices, automotive components, protective gear, greenhouses, Digital Disks (CDs, DVDs, and Blu-ray), and exterior lighting fixtures.Polycarbonate also has very good heat resistance and can be combined with flame retardant materials without significant material degradation.Polycarbonate plastics are engineering plastics in that they are typically used for more capable, robust materials such as in impact resistant “glass-like” surfaces.


Another feature of polycarbonate is that it is very pliable. It can typically be formed at room temperature without cracking or breaking, similar to aluminum sheet metal. Although deformation may be simpler with the application of heat, even small angle bends are possible without it. This characteristic makes polycarbonate sheet stock particularly useful in prototyping applications where sheet metal lacks viability (e.g. when transparency is required or when a non-conductive material with good electrical insulation properties is required).


QQ图片20181212153105


What are the Characteristics of Polycarbonate?

PC is classified as a “thermoplastic” (as opposed to “thermoset”), and the name has to do with the way the plastic responds to heat. Thermoplastic materials become liquid at their melting point (155 degrees Celsius in the case of Polycarbonat). A major useful attribute about thermoplastics is that they can be heated to their melting point, cooled, and reheated again without significant degradation. Instead of burning, thermoplastics like Polycarbonate liquefy, which allows them to be easily injection molded and then subsequently recycled.

By contrast, thermoset plastics can only be heated once (typically during the injection molding process). The first heating causes thermoset materials to set (similar to a 2-part epoxy) resulting in a chemical change that cannot be reversed. If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn. This characteristic makes thermoset materials poor candidates for recycling.

Polycarbonate is also an amorphous material, meaning that it does not exhibit the ordered characteristics of crystalline solids. Typically amorphous plastics demonstrate a tendency to gradually soften (i.e. they have a wider range between their glass transition temperature and their melting point) rather than to exhibit a sharp transition from solid to liquid as is the case in crystalline polymers.Lastly, Polycarbonate is a copolymer in that it is composed of several different monomer types in combination with one another.


18-11-22


Is PC Toxic?

There is a potential that certain types of polycarbonate could be hazardous in food contact situations due to the release of Bisphenol A (BPA) during hydrolysis (degradation due to material contact with water)1. The most commonly made types of polycarbonate are created by the combination of BPA and COCl2, however, there are BPA free polycarbonates that have become particularly marketable for applications involving perishable food or water.

There have been roughly 100 studies conducted on BPA and the results are somewhat controversial in that a correlation between funding source and risk assessment has been shown to exist. Most studies with government funding showed BPA to be a hazardous risk to health while many with industry funding showed lower to no medical risks. Regardless of the contradictory studies on the negative effects of BPA, certain types of Polycarbonate have been associated with its release. This has led to the advent of “BPA-Free” polycarbonate products (commonly shown on consumer products such as canning jars).










Related Industry Knowledge

Copyright © Guangzhou Hujiang Lighting Electric Co.,Ltd All Rights Reserved.