The ornamental design for a plasticthermalbarrier for use in constructing thermally insulated windows, doors, and/or frames and the like, substantially as shown and described.
FIG. 1 is a perspective view of a plastic thermal barrier for use in
constructing thermally insulated windows, doors, frames and the like,
shown fragmentarily to indicate indeterminate length;
FIG. 2 is a sectional view thereof taken along line 2--2 of FIG. 1;
FIG. 3 is a top plan view thereof, the other side being a mirror image
thereof.