Pyrolysis Gas Chromatography Mass Research Articles

Phytochemical composition of Tibetan tea fermented by Eurotium cristatum and its effects on type 1 diabetes mice and gut microbiota

“Golden-flower” Tibetan tea (GTT) is an innovative dark tea fermented via fungus Eurotium cristatum. To study GTT effects on alleviating the symptoms of type 1 diabetes mellitus (T1DM), GTT's extract (GTTE) was prepared. GTTE chemical compositions were analyzed via HPLC, pyrolysis-gas chromatography-mass (Py-GC-MS) spectrometry analysis, and chemistry analyses. GTTE effects on T1DM were explored on T1DM mice model induced by streptozotocin (STZ). GTTE was composed mainly of tea pigment theabrownin (TB) (49.18%), with high percentages of polysaccharide (16.93%), protein (10.15%), polyphenols (13.90%), amino acids (5.89%), caffeine (1.83%), and flavonoids (0.67%). Py-GC-MS results exhibited that GTTE constituted of phenols, lipids, sugars, and proteins. GTTE attenuated T1DM conditions of mice, relieved their liver and pancreatic injury, restored damaged islet cells, decreased oxidative stress by increasing superoxide dismutase (SOD) and catalase (CAT) levels, modulated cytokine expression leading to the decreasing pro-inflammatory cytokines TNF-α and IL-6, increased anti-inflammatory cytokines IL-4 to improve inflammatory responses, and optimized gut microbiota composition and structure based on high-throughput 16S rDNA sequencing, suggesting multi-channel anti-diabetes mechanisms.

A novel halogen-free flame-retardant fabrication for the study of smoke suppression and flame retardancy of polystyrene

A novel P–N flame-retardant (PON) was synthesized by nucleophilic substitution reaction using diphenyl phosphoryl chloride and piperazine as raw materials. Its chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR), liquid-state nuclear magnetic resonance (NMR), high resolution mass spectrometry (HEMS) and elemental analysis, and its thermal stability by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Subsequently, five char-forming agents, namely pentaerythritol (PER), chitosan (CTS), lignin (LI), graphene (GN) and expandable graphite (EG), were selected to form five intumescent flame-retardants in a 1:1 mass ratio with PON. Polystyrene (PS) composites were prepared by melt blending method. The synergistic effect of PON and different char-forming agents on thermal stability, combustion behavior and flame retardancy of PS composites were systematically investigated. The results showed that the PS/10% PON/10% EG composite had the highest limiting oxygen index (LOI) value of 25.8%, and the cone calorimetric test showed that the peak heat release rate (pHRR), total heat release rate (THR), and total smoke release (TSP) of the composite were reduced by 74.6%, 24.4% and 43.6%, respectively, compared with neat PS, and this composite exhibited the most excellent flame retardancy. Finally, the flame-retardant mechanism of PS/10% PON/10% EG composite was discussed and proposed by the results of scanning electron microscope (SEM), thermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG-IR), and pyrolysis-gas chromatography-mass (PY-GC/MS) measurements in detail.

Physicochemical Properties, Thermal Stability, and Pyrolysis Behavior of Antioxidative Lignin from Water Chestnut Shell Obtained with Ternary Deep Eutectic Solvents.

The molecular weight of lignin extracted from lignocellulosic biomass is an important factor in determining its valorization in industrial processes. Herein, this work aims to explore the extraction of high molecular weight and bioactive lignin from water chestnut shells under mild conditions. Five kinds of deep eutectic solvents were prepared and applied to isolate lignin from water chestnut shells. The extracted lignin was further characterized with element analysis, gel permeation chromatography, and Ultraviolet-visible and Fourier-transform infrared spectroscopy. The distribution of pyrolysis products was identified and quantified with thermogravimetric analysis-Fourier-transform infrared spectroscopy and pyrolysis-gas chromatograph-mass spectrometry. The results showed that choline chloride/ethylene glycol/p-toluenesulfonic acid (1:1.8:0.2 molar ratio) exhibited the highest fractionation efficiency for lignin (84.17% yield) at 100 °C for 2 h. Simultaneously, the lignin showed high purity (90.4%), high relative molecular weight (37,077 g/mol), and excellent uniformity. Furthermore, the aromatic ring structure of lignin remained intact, consisting mainly of p-hydroxyphenyl, syringl, and guaiacyl subunits. The lignin generated a large number of volatile organic compounds during the depolymerization process, mainly composed of ketones, phenols, syringols, guaiacols, esters, and aromatic compounds. Finally, the antioxidant activity of the lignin sample was evaluated with the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay; the lignin from water chestnut shells showed excellent antioxidant activity. These findings confirm that lignin from water chestnut shells has a broad application prospect in valuable chemicals, biofuels and bio-functional materials.

Pyrolytic kinetics, reaction mechanisms and gas emissions of waste automotive paint sludge via TG-FTIR and Py-GC/MS

The present study experimentally quantified the pyrolysis behaviors of waste solvent-based automotive paint sludge (OAPS) and water-based automotive paint sludge (WAPS) at four different heating rates using thermogravimetric-Fourier transform infrared (TG-FTIR) spectrometry and pyrolysis-gas chromatography-mass (Py-GC/MS) spectrometry analyses. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods combined with the master-plots method were employed to investigate the pyrolysis kinetics and reaction mechanisms of waste automotive paint sludge. Three reaction stages and three reaction peaks in stage 2 were distinguished for both OAPS and WAPS degradation. The average activation energy (Ea) estimates for OAPS (FWO: 179.09 kJ/mol; KAS: 168.28 kJ/mol) were slightly higher than WAPS (FWO: 175.90 kJ/mol; KAS: 164.80 kJ/mol) according to FWO and KAS methods. The main pyrolysis reaction mechanisms of both OAPS and WAPS closely matched with the order-based model corresponding to 3rd and 2nd order random nucleation on an individual particle. The evolved gas species of CH4, CO2, phenols, NH3, H2O, and CO from OAPS and WAPS pyrolysis were identified by TG-FTIR. According to Py-GC/MS, hydrocarbons (47.2%) and O-components (42.7%) were relatively large after OAPS and WAPS pyrolysis, respectively. Melamine was the most abundant N-component product after pyrolysis of OAPS (5.8%) and WAPS (4.8%).

Thermal degradation and pyrolysis behavior of wholly aromatic phosphorus-containing thermotropic liquid crystal copolyesters

In this study, the thermal degradation and pyrolysis behavior of three wholly aromatic phosphorus-containing thermotropic liquid crystal copolyesters (TLCP) were investigated. The non-isothermal degradation kinetic parameters were determined using the Kissinger and Friedman method. The copolyesters exhibited two degradation stages in air but only one in N2, and better thermal stability was observed for those containing more 10-(2,5-Dihydroxypheny)-10 h-9-oxa-10-phospha-phe-nanthrene-10-oxide (DOPO-HQ) units, which could be reflected by the thermogravimetric analyzer (TGA) data and E values. The TGA coupled with Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis-gas chromatograph-mass spectrometer (Py-GC-MS) results showed that DOPO-HQ decomposed first in the early stage of degradation, generating gaseous pyrolysis products and forming phosphorus-containing char residue in the later stages of degradation. However, the copolyesters produced more CO2 and less organic volatiles during thermal oxidative degradation. The morphology and FTIR spectra of the char residue obtained after TGA experiments showed a continuous and dense structure due to the presence of phosphorus moieties. The microscale combustion calorimeter (MCC) and limiting oxygen index (LOI) results showed that the copolyesters have excellent flame retardant properties, and the LOI value increases monotonically with increasing of DOPO-HQ content, having a maximum value up to 73.8%, due to its excellent gas-phase and condensed-phase fire inhibition mechanisms. Overall, the resulted phosphorus-containing thermotropic liquid crystal copolyesters exhibited excellent thermal stability and flame retardancy, the thermal degradation and pyrolysis research would be a good guidance for its processing and application.

Microplastic Mass Concentrations and Distribution in German Bight Waters by Pyrolysis-Gas Chromatography-Mass Spectrometry/Thermochemolysis Reveal Potential Impact of Marine Coatings: Do Ships Leave Skid Marks?

In this first mass-related survey of microplastics (MPs, <1 mm) in the German Bight (North Sea, 2.5 m water depth), spatial load, temporal variations, and potential sources were examined. Relevant plastic types were detected using pyrolysis-gas chromatography-mass spectrometry/thermochemolysis (Py-GC/MS). This suitable method provides qualitative and trace-level polymer or polymer cluster-specific mass quantitative MP data. Neither MP concentration (2-1396 μg m-3) nor type distribution was homogeneous. Concentrations appeared to be substantially influenced by meteorological and oceanographic conditions. The coastal MP-type composition showed an overprint indicating a packaging waste-related signal. Considerably different compositions were observed in central and estuarine areas. Here, a close relation to marine (antifouling) coating particles, i.e., abrased chlorinated rubber-, acryl-styrene-, and epoxide binder-containing particles are hypothesized as the main MP source, indicating ship "skid marks". They represent a dominant, toxicologically relevant but underestimated marine-based MP share, inverting the widely cited 80% terrestrial- to 20% marine-based debris ratio for MPs. In consequence of the findings, polymer clusters attributed to the basic polymers polyethylene, polypropylene, polystyrene, poly(ethylene terephthalate), poly(vinyl chloride), poly(methyl methacrylate), and polycarbonate are proposed for Py-GC/MS MPs mass determination based on specific thermal decomposition products linked to related polymer structural units.

Effects of pyrolysis parameters on the distribution of pyrolysis products of Miscanthus

This work presents a comprehensive study on the effects of pyrolysis parameters (pyrolysis temperature, residence time, and heating rate) on the distribution of pyrolysis products of Miscanthus. Py-GC/MS (Pyrolysis-gas chromatography/mass) was conducted to identify building blocks of value-added chemical from Miscanthus. The results showed that the main pyrolysis products of Miscanthus were ketone, aldehyde, phenol, heterocycles, and aromatic compounds. The representative compounds of ketone and aldehyde compounds produced at different pyrolysis temperatures changed obviously, while the representative compounds of phenolic, heterocyclic, and aromatic compounds had no obvious change. Large-scale pyrolysis of Miscanthus had begun at 400°C, and the relative content of pyrolysis products from Miscanthus reached the maximum of 98.34% at 700°C. The relative peak area ratio of phenol and aromatic compounds reached the maximum and minimum at the residence time of 5 and 10 s, while the relative peak area ratio of ketone compounds showed the opposite trend. The relative peak area ratio of aldehyde compounds was higher under shorter or longer residence time. For heterocyclic compounds, the relative peak area ratio reached the maximum of 27.0% at residence time of 10 s. The faster or slower heating rate was beneficial to the production of aldehyde and phenol compounds. The relative peak area ratio of ketone compounds reached the maximum at 10,000°C/s, 70°C/s, and 10°C/s, and the relative peak area ratio tendency of heterocyclic compounds was similar to ketone. For aromatic compounds, the overall fluctuations were large, and the relative peak area ratio was the highest at the heating rate of 100°C/s.

PHYSICAL AND MECHANICAL PROPERTIES OF GLUED-LAMINATED LUMBER FROM FAST-GROWING TREE SPECIES USING MAHOGANY TANNIN ADHESIVE

Tannin from mahogany bark extract contains polyphenols that could be used in adhesives. In this study, tannin (T) was reacted with resorcinol (R) and formaldehyde (F) at a ratio of 100:3:5 (w/w/w) under alkaline conditions to make an adhesive. The physical–chemical properties of tannin and TRF adhesive were assessed. Three-layer glued–laminated lumber (glulam) made with wood from jabon (Anthocephalus cadamba), pine (Pinus merkusii), and sengon (Falcataria moluccana) was bonded using TRF with a glue spread of 280 g/m2, cold pressed at 1.47 MPa for 4 h, and then clamped for 24 h. Glulam physical–mechanical properties were tested based on Japanese Agricultural Standard (JAS) 234-2007. Comparison of the physical properties of mahogany tannin and TRF showed that the solids content of mahogany tannin increased after becoming TRF. Compared with phenol resorcinol formaldehyde (PRF) resins, TRF had a similar appearance and specific gravity, but differed in solids content, viscosity, and gel time. Matrix-assisted laser desorption/ionization (MALDI)-time of flight mass (TOF) spectra revealed that mahogany tannin could be classified as hydrolyzable, and pyrolysis Gas Chromatograph-Mass Spectroscopy (GC-MS) showed that the phenolic content was 8.87%. Copolymerization in TRF was indicated by a shift in wave number in Fourier transform IR, reduced percentage of the phenolic component, and increased pH and melting temperature. Mahogany tannin could be prepared for cold-set TRF glulam adhesive, and all glulams fulfilled JAS 234-2007 with regard to MC and MOR. Although TRF adhesive contained a small amount of resorcinol, it was suitable for low density wood, and in dry condition performed equal to PRF.

Comparative study on thermal cracking characteristics and bio-oil production from different microalgae using Py-GC/MS

The yield and chemical composition of pyrolysis products of Chlorella pyrenoidosa and Schizochytrium limacinum were determined using thermogravimetric analyzer (TGA) and pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) by varying the temperature ranges. After further analysis of the total ion current (TIC) diagrams of Chlorella pyrenoidosa and Schizochytrium limacinum, it was concluded that both the pyrolysis products of each sample were mainly comprised of hydrocarbons, aromatics, fatty acids, nitrogen compounds, PAHs, phenols, etc, however, the relative content of each compound from Chlorella pyrenoidosa and Schizochytrium limacinum was different. The pyrolysis of Chlorella pyrenoidosa and Schizochytrium limacinum at 350°C produced a maximum yield of bio-oil production (44.32% and 60.99%); moreover, Chlorella pyrenoidosa could lead to more pollutants (nitrogen compounds and PAHs) release (2.71%) compared to that of Schizochytrium limacinum (0.7%). Considering the reasonable bio-oil production and minimum release of pollutants, Schizochytrium limacinum was found to be superior for producing biofuel against Chlorella pyrenoidosa. Keywords: microalgae, Chlorella pyrenoidosa, Schizochytrium limacinum, bio-oil production, thermal cracking, Py-GC-MS DOI: 10.25165/j.ijabe.20191201.3628 Citation: Li G, Ji F, Bai X, Zhou Y G, Dong R J, Huang Z G. Comparative study on thermal cracking characteristics and bio-oil production from different microalgae using Py-GC/MS. Int J Agric & Biol Eng, 2019; 12(1): 208–213.

Effect of autogenous pressure on volatile pyrolysis products

The thermal decomposition of wood, conducted in the absence of oxygen, includes so-called primary and secondary reactions, where secondary reactions are regarded as those involving previously formed decomposition products. This study uses a pyrolysis–gas chromatograph-mass spectrometer, Py-GC/MS, to investigate the degree to which secondary reactions affect the composition of the volatile pyrolysis gases. Samples were Monterey Pine (Pinus radiata) and were held in either open crucibles or sealed capsules. For specified heating profiles ranging from 240 to 700 °C, volatiles escaped soon after they evolved in the open crucibles but in the sealed capsules they were retained at high pressures for long residence times. Differences were observed over the entire range of treatment temperatures, which suggests that secondary reactions occur concurrently to primary reactions and implies that they are more dependent on vapour-phase concentration than on temperature. In comparison to the open crucible experiments, the sealed capsule experiments produced more low molecular weight pyrolysis products and more long chain alkanes, alkenes and methyl ketones, but at the expense of extractives, carbohydrate and lignin derivatives. The sealed capsules also had less oxygen in the condensable fraction, characterised by the presence of alkyl substituted compounds. Instead the open crucible experiments contained methoxyl substituted compounds. These differences are all characteristic of secondary reactions. This study shows that controlling the extent of secondary reactions is an invaluable tool for optimising pyrolysis.

Pyrolysis characteristics analysis of Chang-7 oil shale using thermal analysis and pyrolysis-gas chromatograph-mass spectrometry

There are vast resources of oil shale in the Chang-7 section of the Upper Triasic Yanchang Formation, Ordos Basin, China. They would provide secure access to transportation fuels, if utilized in an effective, economic and environmental manner. A Chang-7 oil shale sample containing pyrite has been pyrolysed in a thermogravimetric analyzer at constant heating rates of 5, 10, 20℃/min up to 1150℃ with nitrogen as purge gas. Meanwhile, the pyrolysis-gas chromatograph-mass spectrometry experiments were performed on parallel samples of Chang-7 oil shale sample at 20℃/min in the four temperature sections, ranging from 100 to 700℃ to understand the decomposition mechanism. The initial decomposition temperature and the final decomposition temperature of hydrocarbonaceous material were about 367℃ and 521℃ (average values), respectively, which raised with the increase of heating rate. The decomposition of pyrite began to take place over 500℃, and the pyrolysates involving sulfur compounds are harmful to the environment and corrode the equipment. Thus, we recommended that the final temperature of Chang-7 oil shale pyrolysis was best not to exceed 550℃ considering the heating rate to avoid environmental pollution and damage of the instruments. Chang-7 oil shale exhibited a single stage decomposition in the range of about 367–521℃, representing the rearrangement of kerogen molecules in the temperature range of 100–350℃. The activation energies of kerogen decomposition were calculated using Coats–Redfern method at different heating rate. We found that both activation energy and pre-exponential factor increased with an increasing heating rate. Finally, the DTA curves of Chang-7 oil shale verified the reliability of the calculated activation energies.

Fire behavior of novel imidized norbornene-containing poly(ethylene terephthalate) copolymers: Influence of retro-Diels-Alder reaction at high temperature

Retro-Diels-Alder reaction (rDA) has been widely used as a common modification approach for expanding functional applications of polymers. Especially, it has become an effective method of current cross-linking chemistry. With the goal of designing a cross-linkable PET-based copolyester toward flame retardancy and anti-dripping during combustion, dimethyl 5-(1,3-dioxo-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindol-2(3H)-yl) isophthalate (DMTMI) was incorporated as the functional co-monomer into PET chains via random transesterification polycondensation. Thermogravimetry-differential scanning calorimetry (TG-DSC) and rheological studies demonstrated the existence of cross-linking behavior at high temperature. By controlling the co-monomer content, expected flame retardancy was obtained, as illustrated by the results from the limiting oxygen index (LOI) and cone calorimetry. Furthermore, LOI values increased firstly and then decreased with the content of DMTMI increased, which was related to the existence of rDA reaction, and further proposed that a competitive relationship between the release of inflammable cyclopentadiene during rDA reaction and cross-linking behavior occurred in combustion. The hypothesis was verified through pyrolysis-gas chromatograph-mass spectrometry (Py-GC-MS).

Survey of new, single-layer architectural paints

ABSTRACTA total of 1028 samples of architectural paint were collected from store patrons who purchased paint at a medium-sized building supply store in Edmonton, Alberta, Canada. Information about what surfaces the paint would be applied to was collected from each customer at the time of purchase and the data summarized. The samples were characterized by colour, Fourier transform infrared spectroscopy (FTIR), pyrolysis gas chromatograph-mass spectrometry (py-GC-MS), and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). After visual colour comparison and FTIR analysis alone, 700 samples could be uniquely identified while the remaining 328 samples were divided into 98 groups, representing 956 indistinguishable pairs; the results after application of these two techniques gave a calculated discrimination power of 99.82%. The application of py-GC-MS and SEM-EDS to the remaining indistinguishable pairs gave only a very modest improvement in further distinguishing the samples. Information about current colour trends and which objects are most likely to be painted, or re-painted, by the general public is also provided.

Temperature-Oriented Pyrolysis on the Decomposition Characteristics of Chlorella pyrenoidosa

Abstract Chlorella pyrenoidosa is one of the best candidates for biofuel production. The yield and chemical composition of decomposed products of Chlorella pyrenoidosa were determined using thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), and pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) by varying the temperature ranges. The results indicated that the main decomposition temperature of Chlorella pyrenoidosa was 294.53°C and up to 46.7% of the mass was lost. A complete decomposition of Chlorella pyrenoidosa was detected until 642.64°C. The pyrolysis of Chlorella pyrenoidosa at 800°C produced 63.58% (the maximum yield) of pyrolysis products compared to 40.22% at 300°C. It is suggested that the generation of pollutants during microalgae pyrolysis can be avoided by controlling the temperature at a relatively low stage (approximately 300°C).

Rapid pyrolysis behavior of oleaginous microalga, Chlorella sp. KR-1 with different triglyceride contents

Rapid pyrolysis of two Chlorella sp. KR-1 samples, with triglyceride content of 23.8 and 44.9wt%, was conducted using pyrolysis gas chromatograph-mass spectrometry over a temperature range (400–600 °C). The effects of triglyceride content of the microalgal cells and pyrolysis temperature on the structure and distribution of products were analyzed and the pyrolysis products were classified according to number of carbons and chemical species. The triglyceride content of microalgal cells was found to affect the concentration of free fatty acids, hydrocarbons, and derivatives of carbohydrates. In the case of the lipid-rich sample, free fatty acids originating from triglyceride decomposition were found to be the predominant compounds whereas sugar-dehydrated products such as anhydroglucose were the predominant compounds in the case of the lipid-poor sample.

Evidence of martian perchlorate, chlorate, and nitrate in Mars meteorite EETA79001: Implications for oxidants and organics

The results from the Viking mission in the mid 1970s provided evidence that the martian surface contained oxidants responsible for destroying organic compounds. In 2008 the Phoenix Wet Chemistry Lab (WCL) found perchlorate (ClO4-) in three soil samples at concentrations from 0.5 to 0.7wt%. The detection of chloromethane (CH3Cl) and dichloromethane (CH2Cl2) by the Viking pyrolysis gas chromatograph–mass spectrometer (GC–MS) may have been a result of ClO4- at that site oxidizing either terrestrial organic contaminates or, if present, indigenous organics. Recently, the Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory (MSL) Curiosity directly measured the presence of CH3Cl, CH2Cl2 and, along with measurements of HCl and oxygen, indirectly indicate the presence of ClO4-. However, except for Phoenix, no other direct measurement of the ClO4- anion in martian soil or rock has been made. We report here ion chromatographic (IC) and isotopic analyses of a unique sawdust portion of the martian meteorite EETA79001 that show the presence by mass of 0.6±0.1ppm ClO4-, 1.4±0.1ppm ClO3-, and 16±0.2ppm NO3- at a quantity and location within the meteorite that is difficult to reconcile with terrestrial contamination. The sawdust sample consists of basaltic material with a minor salt-rich inclusion in a mass ratio of ∼300:1, thus the salts may be 300 times more concentrated within the inclusion than the whole sample. The molar ratios of NO3-:ClO4- and Cl-:ClO4-, are very different for EETA79001 at ∼40:1 and 15:1, respectively, than the Antarctic soils and ice near where the meteorite was recovered at ∼10,000:1 and 5000:1, respectively. In addition, the isotope ratios for EETA79001 with δ15N=−10.48±0.32‰ and δ18O=+51.61±0.74‰ are significantly different from that of the nearby Miller Range blue ice with δ15N=+102.80±0.14‰ and δ18O=+43.11±0.64‰. This difference is notable, because if the meteorite had been contaminated with nitrate from the blue ice, the δ15N values should be the same. More importantly, the δ15N is similar to the uncontaminated Tissint Mars meteorite with δ15N=−4.5‰. These findings suggest a martian origin of the ClO4-, ClO3- and NO3- in EETA79001, and in conjunction with previous discoveries, support the hypothesis that they are present and ubiquitous on Mars. The presence of ClO3- in EETA79001 suggests the accompanying presence of other highly oxidizing oxychlorines such as ClO2- or ClO−, produced both by UV oxidation of Cl− and γ- and X-ray radiolysis of ClO4-. Since such intermediary species may contribute to oxidization of organic compounds, only highly refractory and/or well-protected organics are likely to survive. The global presence of ClO4-, ClO3-, and NO3-, has broad implications for the planet-wide water cycle, formation of brines, human habitability, organics, and life.

Yield and Characteristics of Pyrolysis Products Obtained from Schizochytrium limacinum under Different Temperature Regimes

Pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) was used to determine the yield and chemical composition of the pyrolysis products of Schizochytrium limacinum. The pyrolysis was carried out by varying the temperature from 300 °C to 800 °C. It was found that the main decomposition temperature of Schizochytrium limacinum was 428.16 °C, at which up to 66.5% of the mass was lost. A further 18.7% mass loss then occurred in a relatively slow pace until 760.2 °C due to complete decomposition of the ash content of Schizochytrium limacinum. The pyrolysis of Schizochytrium limacinum at 700 °C produced the maximum yield (67.7%) of pyrolysis products compared to 61.2% at 400 °C. While pollutants released at 700 °C (12.3%) was much higher than that of 400 °C (2.1%). Higher temperature will lead to more pollutant (nitrogen compounds and PAHs) release, which is harmful to the environment. Considering the reasonably high yield and minimum release of pollutants, a lower pyrolysis temperature (400 °C) was found to be optimum for producing biofuel from Schizochytrium limacinum.

Pyro-GC/MS and thermal degradation studies in polystyrene–poly(vinyl chloride) blends

The blends of polystyrene (PS) using various proportions of poly(vinyl chloride) (PVC) were prepared and the thermal decomposition temperatures of these blends were measured from the dynamic thermogravimetric analysis (TGA) carried out under inert atmosphere from ambient to 800 °C at different heating rates. Kinetic parameters of the degradation process in pure PS and its blends with various proportions of PVC were calculated. Activation energy of the degradation process in the blends was found to increase with the inclusion of small amount of PVC in PS. The stabilization effect on PS varies with the heating rates and the composition of the blends. The pyrolysis gas-chromatographic mass spectrometry (Py-GC/MS) studies were also carried out over a range of temperature (330–370 °C) and the intensity of major ions produced during pyrolysis were separated and measured though GC/MS. Using a small amount of PVC in the matrix showed a marked reduction in the major pyrolysis products of PS. The stabilization of PS in the blends has been explained by a mechanism involving interaction between the degrading products from the polymer components leading to a stable polymer network. The extent of interaction is affected by the changing morphology of the blends with composition.

Thermal behaviour of fentanyl and its analogues during flash pyrolysis

Flash pyrolysis of fentanyl and its analogues has been studied on pyrolysis-gas chromatograph-mass spectrometer (Py-GC-MS) system. Initial pyrolytic fragmentation of these compounds led to the formation of N-substituted-1,2,5,6-tetrahydropyridine and N-phenylpropanamide as the primary pyrolytic products. Moreover, depending up on the furnace temperature, these pyrolytic products can also undergo further fragmentation to give different compounds. We, herein, discuss the probable fragmentation routes of parent as well as pyrolytic products. This study will be useful while developing technologies for thermal aerosol generation of fentanyl and related compounds.

Effects of pretreated polysulfonamide pulp on the ablation behavior of EPDM composites

Abstract Excellent ablative properties of ethylene–propylene–diene elastomer (EPDM) composites were obtained by adding pretreated polysulfonamide pulp (PSA-pulp). The effects of pulp pretreatment and pulp content on the mechanical and ablative properties of PSA-pulp/EPDM composites were studied. Experimental results showed that the tensile strength decreased slightly and the ablative properties increased by 3 folds on addition of 10 phr pretreated PSA-pulp. This significant improvement in the ablative properties was attributed to the enhanced dispersion degree and improved interfacial adhesion of pretreated PSA-pulp to EPDM matrix, which were observed from scanning electron microscopy. The ablation behavior of pretreated PSA-pulp/EPDM composites was proposed in accordance with the characterizations of thermogravimetric analysis (TGA), energy disperse X-ray spectroscopy (EDS) and pyrolysis-gas chromatograph–mass spectrometry (Py-GC–MS). The carbonized PSA-pulp acted as a skeleton in retaining the char layer and reduced the material loss during the high temperature ablation.