Plastic & UV - Materials Question

Folks,
have recently made a prototype holder for a UV lamp, its is one of these
anti bacteria units. Used gray PVC, but after about 30 hours it became
brittle, well customer dropped and it fractured into many bits!
Can anybody recommend a material for this application, one for machining
a prototype, and if possible for injection moulding when in production.
Personally was thinking of HDPE or PP they are chemically pretty stable.

any suggestions

John