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Kompozyty polimerowe podatne na (bio)degradacjêStreszczenie -Na podstawie przegl¹du literatury (obejmuj¹cej publikacje a¿ do roku 2007 w³¹cznie) scharakteryzowano metody wytwarzania i niektóre w³aoeciwooeci u¿ytkowe mieszanin polimer syntetyczny/skrobia ze szczególnym uwzglêdnieniem mo¿liwooeci zwiêkszenia podatnooeci na biodegradacjê tego rodzaju uk³adów na podstawie polietylenu. W ramach badañ w³asnych okreoelono wp³yw wprowadzenia 10 % samego epoksydowanego kauczuku naturalnego (ENR) lub mieszaniny ENR z nadtlenkiem dikumylu (DCP) na biodegradacjê otrzymywanych metod¹ reaktywnego wyt³aczania kompozytów polietylenu lub polipropylenu zawieraj¹cych 60 % skrobi plastyfikowanej gliceryn¹ (SG). Stwierdzono, ¿e po 36 miesi¹cach przebywania próbek w glebie ubytek masy wynosi 30-35 % w zale¿nooeci od sk³adu kompozytu, przy czym ubytek ten zwi¹zany jest g³ównie z degradacj¹ fazy skrobiowej. Zmiany w³aoeciwooeci mechanicznych podczas rozci¹gania w toku trwaj¹cego do 36 miesiêcy testu glebowego sugeruj¹ tak¿e istotne zmiany struktury matrycy poliolefinowej, zw³aszcza sieciowanie PE i degradacjê PP. Na zaobserwowane zmiany istotny wp³yw wywiera obecnooeae dodatków (ENR, DCP), czas degradacji oraz odczyn gleby. S³owa kluczowe: biodegradacja w glebie, polietylen, polipropylen, plastyfikowana skrobia, kompozyt, w³aoeciwooeci mechaniczne. POLYMER COMPOSITES SUSCEPTIBLE TO BIODEGRADATIONSummary -On the basis of the literature data (review covering publications up to 2007) the methods of preparation and some useful properties of the systems synthetic polymer/starch were characterized. Especially the possibility to increase the susceptibility to degradation of the systems based on polyethylene/starch with compatibilizers or polyesters (polycaprolactone)/starch made by reactive extrusion has been discussed. The results of own research concerned the effect of the introduction of 10 % of epoxidized natural rubber (ENR) or the mixture of ENR with dicumyl peroxide (DCP) into the composites of polyethylene or polypropylene (produced by reactive extrusion), containing 60 % of starch plastified with glycerol (SG), on their biodegradation (Table 1). It was found that after 36-month hold time of the samples in the soil, the weight loss was in the range 30-35 % dependently on the composition (Fig. 1) but of course the weight loss concerned mainly the starch phase (Table 1). Changes of tensile properties during 36-month soil test ( Fig. 2 and 3) suggest also significant changes in the structure of polyolefin matrix, especially PE crosslinking and PP degradation. These observed changes are strongly dependent on the presence of additives (ENR, DCP), degradation time and soil reaction.

Blends of aliphatic polyamides (PA6, PA66, and PA12), containing 0 -15 wt % nonepoxidized or epoxidized elastomers (statistical copolymer butadiene-styrene BS/EBS or linear block copolymer styrene-butadiene-styrene SBS/ESBS) were investigated. For PA6-elastomer blends, taken as an example, it was shown that with increasing blending time, mechanical properties of blends increase, especially, if ESBS copolymer is used. It can be treated as an indirect sign of reactions between components. It was also found that in blends considerable changes of glass temperatures of components occur. Polyamides in blends with elastomers have smaller heats of fusion in comparison with virgin polyamides. It testifies to hindering of PA crystallization by elastomers. In some cases, significant shifts of melting points are also observed. Measurements of water contact angle show that all blends have very similar values of contact angles, which are lower than those of virgin polyamides. Elastomer content does not also affect the blend water uptake. However, it depends on the polyamide and elastomer type contrary to contact angle. Highest water uptake changes are observed in blends of PA66, especially for epoxidized elastomers.