[New guidelines for the gum collecting and packaging]
2000
Carvalho, J.S.
In light of a highly justified claim against gum collecting in order to reduce their loss and to avoid impurities, a proposal has been made to make several improvements to the usual PE collectors. To obtain an accurate evaluation of any monoterpenic loss, a integral gm collection was obtained from several Pinus, in which an average turpentine content of 32% from the Pinus pinaster gum, and at 30% on Pinus pinea gum was obtained. These values are much higher than those observed on the opened on the wounded PE collectors; and were much lower after industrial distillation. In the present study on the behavior of opened and closed collectors for Pinus pinaster and Pinus pinea gums, it is shown that the LDPE have to be excluded for use, since the turpentine loss is very large even up to exhaustion of the gum volatile terpenes. The collector wall thickness was 1 to 1.5mm. The terpene loss will obviously be even higher and faster through any LDPE thin wall bags still used. Oppositely, the well closed HDPE collectors on the wound perfectly recommended without loss for periods of no more than two months, but only for Pinus pinaster. For Pinus pinea gums, even the HDPE permits high losses and its application on any type of closed or opened collector should be excluded. More recent experiments indicate greater success by using other polymeric materials such as PT (terephtalic - ethylene glicol polyester) in adequate collectors closing the wound
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