Reflective Earth published an analysis for helping to develop less absorptive and more reflective shade fabrics along with test results for seven fabrics.

White polyethylene film sold as shade fabric with claimed 50-55% shade factor from embedded particles of titanium dioxide and UV neutralizing chemicals, when folded into 6 layers, absorbs 15% of solar energy, reflects 76%, and transmits 9%.  Similar material knitted into a mesh that allows air passage absorbs 28%, reflects 61%, and transmits 11% when folded into 4 layers.  If the absorption can be reduced and the reflection increased, the fabrics will be more effective for use in cities to reduce urban heat island effects and reduce global warming.  The most reflective commercially available fabric reflects 92% and absorbs only 3% while transmitting 5% when folded into 2 layers.  This sets an upper limit to what can be achieved because this material needs modification to resist UV damage.