The combined evidence from chemical kinetics, analytical chemistry, cotton content, and pyrolysis/ms proves that the material from the radiocarbon area of the shroud is significantly different from that of the main cloth. The radiocarbon sample was thus not part of the original cloth and is invalid for determining the age of the shroud.
I have found a few copies of the full paper online. Here is one link:
More information: Ray Rogers summarizing in Thermochimica Acta