JOURNAL OF MATERIALS SCIENCE 40 (2 0 0 5 ) 4189 – 4198 Photo- and bio-degradation processes in polyethylene, cellulose and their blends studied by ATR-FTIR and Raman spectroscopies * D. O  LDAK, H. KACZMAREK † Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Toru´ n, Poland E-mail: halina@chem.uni.torun.pl T. BUFFETEAU, C. SOURISSEAU Laboratoire de Physico-Chimie Mol ´ eculaire, LPCM-UMR5803 CNRS, Universit ´ e Bordeaux1, 351 cours de la lib ´ eration, 33405 Talence Cedex, France Polyethylene, cellulose and their blends with different compositions (5–30% cellulose content) were exposed to UV radiation or composted in soil for bio-degradation. Both types of degradation were carried out under laboratory conditions (room temperature, air atmosphere). The course of degradation processes has been studied using ATR-FTIR and Raman spectroscopies. There are practically no changes in spectra of photo- or bio-degraded pure PE films and cellulose powders. In contrast, the PE/cellulose blends are less stable than pure components and the processes of photodegradation seem to depend on blend composition and irradiation time. Prolonged UV exposure (100 h) leads to efficient photo-oxidation of blends studied. Biodegradation effect was also pronounced in PE films containing 30% cellulose. C  2005 Springer Science + Business Media, Inc. 1. Introduction Polyolefins are very important and useful synthetic polymers because they posses good properties, well- known technology of production and low cost. At present, there is not expedient to back away from using synthetic polymers. A representative polyolefin is polyethylene (PE), which has been extensively studied for many years [1–13]. Even though the mechanism of photochemical and thermal degradation of PE is well understood, the knowledge of the behaviour of this polymer in blends with other synthetic or natural materials is not suffi- cient. It was confirmed in numerous publications that physico-chemical properties of polymer blends are not a simple superposition of component properties [14– 17]. The lack of additivity of polymer properties in blends is a main reason for difficulties in predicting their life-time. The wide use of polymers in many industrial and domestic fields causes ecological problems connected with their utilization. Some synthetic plastics includ- ing polyolefins are characterized by relatively high sta- bilities under both photochemical and environmental conditions. The use of natural or synthetic photo- and bio-degradable polymers is promising, but still prob- lematic, in direction of packaging materials [18–32]. Biodegradable materials are mainly produced for med- ical and pharmaceutical applications; the cost of their ∗ Spectroscopic measurements were performed during EU Marie Curie Training Site Fellowship at University Bordeaux1 (France). † Author to whom all correspondence should be addressed. production is rather high as compared to classical syn- thetic polymers obtained from petroleum. Bio- and photo-degradable plastics are also extensively used in agriculture. An important objective is to prepare non-expensive degradable polymers sensitive to natural factors such as sunlight, heat and soil (water) microorganisms. A sim- ple way for obtaining bio- and photo-degradable plas- tics is to modify synthetic polymers by adding polymer agents of natural origin, such as cellulose or starch. The properties of such composites (tensile strength, thermal stability, resistance to bio- and photo-degradation) de- pend on the kind and amount of added modifier, on its dispersion degree in the polymer matrix, on sample morphology, interactions between components, degree of crystallinity, presence of structural defects as well as preparation or processing conditions [22, 31, 33, 34]. The aim of this work was to study the influence of added natural cellulose (Cell) polymer on photo- and bio-degradation of PE. It was also important to get a better insight into the molecular interactions be- tween blend components (PE and Cell) and in their variations during the two types of degradation. So, we have focused this work on studies of surface proper- ties because photo-degradation occurs mainly in thin surface layers of the polymer samples. We have cho- sen especially sensible methods allowing monitoring the changes in surface structure, as Attenuated Total 0022–2461 C  2005 Springer Science + Business Media, Inc. 4189