Analysis of Acrylic and Methacrylic Networks through Pyrolysis-GC/MS

A direct analytical method developed to characterize UV-cured networks based on multi-step pyrolysis-gas chromatography-mass spectroscopy (GC/MS) is presented. Application of the method to characterize (meth)acrylate-based UV-cured networks is discussed. The reversion process of methacrylates is clearly observed during pyrolysis. In contrast, the decomposition of acrylates in high molecular weight degradation products is hardly detected. The potential impact of this technique to elucidate the structural and compositional nature of UV-cured polymeric networks is highlighted.

Experimental Study On Pyrolysis of Rice Straw Catalyzed By CaO/Al2O3-Phosphate Mixture

This paper studied the synergistic effects of CaO or Al2O3 and three potassium phosphates (e.g., KH2PO4, K2HPO4·3H2O and K3PO4·3H2O) in the rice stalk pyrolysis through pyrolysis-gas chromatography-mass spectrometer (Py-GC/MS) experiments. The results show that after co-catalyzed by CaO/Al2O3 and potassium phosphates, the total contents of phenols, aldehydes, acids, LG from most samples decrease and those of ketones increase compared with those catalyzed by potassium phosphates alone. CaO/Al2O3 and potassium phosphates show synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. and are suitable for the production of ketone-rich bio-oil. Dehydration reactions, etc. are further promoted under the co-catalysis of the two catalysts, and some phenols can be converted to benzene products, etc. The contents of acetic acid can decrease to 0. For 50% K3PO4.3H2O impregnated sample, the yields of furans reduce sharply after CaO addition. For most impregnated samples except 50% K2HPO4·3H2O sample and 30%, 50% K3PO4.3H2O, the contents of total furans and furfural increase after Al2O3 addition.

GC-MS analysis of young and mature wild agarwood leaves (Aquilaria malaccensis Lamk) and its antioxidant potential

Agarwood grows wildly in the nature and its leaves may be utilized as raw materials for agarwood tea, especially from Aquilaria species. The study was conducted to determine the chemical compounds in the young and mature leaves of wild gaharu (Aquilaria malaccensis Lamk). Chemical compounds were detected using pyrolysis gas chromatography mass spectrometry (py-GCMS) while antioxidant capacity of the leaf extracts was assayed using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical method. The results obtained a total of 30 chemical compounds in agarwood leaves extract with different composition between young and mature leaves. The agarwood leaves extracts displayed strong antioxidative capacity with a main compound namely octadecanoid acid or stearic acid.

Characterization and identification of Chinese historical rubbings preserved in Wuyuan Museum by Pyrolysis–Gas Chromatography/Mass Spectrometry

For conservation and restoration purposes, the precious historical rubbings preserved in Wuyuan Museum were studied by multi-analytical techniques including 14C radiocarbon dating, scanning electron microscopy (SEM), Pyrolysis–Gas Chromatography/Mass Spectrometry (Py-GC/MS) and Herzberg staining method. The results showed that the Py-GC/MS method is an efficient method for identifying the raw materials of paper and ink in historical rubbings simultaneously. Through Py-GC/MS analysis, five types of constituents could be detected: (1) polycyclic aromatic hydrocarbons (PAHs) from soot; (2) compounds related to tar of conifer wood: retene and methyl dehydroabietate; (3) marker compounds from the whole egg; (4) additive compounds: menthol and curcumene, which were found for the first time in ink; (5) biochemical compounds from bark paper: β-amyrin and α-amyrin. Based on the above results, the ink type, binding media and additives in ink, as well as the fiber origin of the rubbing paper could be concluded. This study could not only provide scientific support for conservation and restoration of the historical rubbings preserved in Wuyuan museum, but also give method guidance for analysis of the uncharacterized rubbings from different origins.

Cheminformatics Applied to Analytical Pyrolysis of Lignocellulosic Materials

Pyrolysis-Gas Chromatography/Mass Spectrometry has been used to characterize a wide variety of polymers. The main objective is to infer the attributes of materials in relation to their chemical composition. Applications of this technique include the development of new improved materials in the industry. Furthermore, due to the growing interest in biorefinery, it has been used to study plant biomass (lignocellulose) as a renewable energy source. This chapter describes a procedure for characterization and classification of polymeric materials using analytical pyrolysis and cheminformatics. Application of omics tools for spectral deconvolution/alignment and compound identification/annotation on the Py-GC/MS chromatograms is also described. Statistical noise is generated by production of numerous small uninformative compounds during pyrolysis. Such noise is reduced by cheminformatics here detailed and this facilitate the interpretation of results. Furthermore, some inferences made by comparison of the identified compounds to those annotated with a biological role in specialized databases are exemplified. This cheminformatic procedure has allowed to characterize in detail, and classify congruently, different lignocellulosic samples, even using different Py-GC/MS equipment. This method can also be applied to characterize other polymers, as well as to make inferences about their structure, function, resistance and health risk based on their chemical composition.