Loss of Chimassorb 944 from LDPE and identification of additive degradation products after exposure to water, air and compost
2001 (English)In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 74, no 1, 103-112 p.Article in journal (Refereed) Published
A low-density polyethylene (LDPE) film containing a hindered amine light stabiliser (Chimassorb 944) was exposed to a composting mixture, chemical hydrolysis at pH 5 and pH 7 and air, in all cases at room temperature and for a period of 4 years. The structural changes of the LDPE film were investigated by differential scanning calorimetry (DSC) and size exclusion chromatography with viscosity detection (SEC-viscosity) while degradation products of LDPE and Chimassorb 944 were identified by gas chromatography-mass spectrometry (GC-MS). Determination of the amount of remaining stabiliser was performed using an ultrasonic extraction technique followed by LN spectroscopy analysis (250 nm, absorption of 1,3,5-triazine group). The ultrasonic extraction of Chimassorb 944 was carried out at 60 degreesC for a period of 1 h, using chloroform as extracting solvent. Loss of the stabiliser accompanied by structural changes of the polymeric matrix occurred during exposition time and was strongly influenced by exposure conditions. Thus, the fastest loss of the stabiliser was found on exposition to chemical hydrolysis at both pH while the slowest loss was observed during ageing in compost. Different products formed from Chimassorb 944 were found in all the tested environments as a result both of degradation of the stabiliser to smaller fragments and of reactions between these fragments and other additives present in LDPE. Thus, (Z)-9-octadecenamide was found in both unexposed and all the tested samples and was formed already during processing. 2,2,6,6-Tetramethyl-4-aminopiperidine was found in air and compost aged samples while 2,4-di-t-butyl-6-nitro-phenol was found in the samples exposed to air and water environments and [2-cyclohexene-1-dione, 3,5-dimethyl, O-methyloxime] were found exclusively in the samples aged in water at pH 5.
Place, publisher, year, edition, pages
2001. Vol. 74, no 1, 103-112 p.
LDPE, Chimassorb 944, additive degradation product, migration, compost, air, low-density polyethylene, stabilizers, biodegradation, mechanism, polymers
IdentifiersURN: urn:nbn:se:kth:diva-20978ISI: 000171263200011OAI: oai:DiVA.org:kth-20978DiVA: diva2:339675
QC 201005252010-08-102010-08-10Bibliographically approved