SD Polymer’s all products are made of raw materials imported overseas. We are willing to offer professional information in the choice of raw materials for reference，so customers are well-informed of qualities and performances of different materials and customers can make a wise choice according to their specific needs．
The main materials used especially for lighting diffusion are PMMA (Acrylic) and Polycarbonate (PC)．While in the fields of environment protection and chemiluminescence illumination, PETG is increasingly used．As for PMMA and PC, the prosperities of them can be further modified to some extent as indicated below：
In general we can say that they provide the foIlowing prosperities in unmodified form：
PMMA：Excellent clarity，excellent UV resistance，medium impact resistance，low flame resistance，Max．working temperature：70℃/80℃.
PC：Good clarity，excellent flame resistance，very light impact resistance，average UV resistance．Max．working temperature：115℃.
We can say that for the majority of lighting applications, PMMA is the right choice because，of all the properties required for a diffuser,resistance to UV yellowing is usually the most cruciaI. In general PC is mostly used for external applications where usual impact is normal, high traffic areas like government buildings, where flame resistance is specified or where heat resistance is needed．
Modification of Prosperities：
The process of impact modification applies to PMMA only and is a process by which a quantity of special impact modifier is mixed with the resin to improve the impact resistance．PMMA is mostly used in impact-modified form depending on the specific application. As impact modifier is added，the optical properties become poorer，but the flexibility and impact strength increases．
PETGs are glycol modified PETs．The resulting molecular structure is irregular and the resin is clear and amorphous with a glass transition temperature of 88℃(190 F).
PETGs can be processed over a wider processing range than conventional PETs and offer good combination of properties such as toughhess，clarity，and stiffness. PETGs offer a desirable combination of properties such as clarity，toughness，and stiffness. Applications include medical devices (test tubes and bottles)，toys，displays and lighting fixtures，face shields，and refrigerator crisper pans.