Molecular Weight Ratio Research Articles

Multi-objective dynamic optimization of seeded suspension polymerization process

The temperature profile of the seeded suspension polymerization process was optimized to maximize molecular weight, shell thickness and monomer conversion ratio of core–shell polymer particles. Extreme learning machine radial basis function neural networks with R2 values greater than 0.93 were developed, to predict polymer properties at any point in time, using data generated by a computational fluid dynamics model. The optimal combination of input parameters for each neural network was selected from a pool of 44 variables, by using a weight-based method that uses a support vector regression model, and a global exhaustive search algorithm, consecutively. The neural networks developed were incorporated into a genetic algorithm that maximizes the molecular weight, monomer conversion ratio and shell thickness. The optimum temperature profile generated by the algorithm satisfactorily maximized all target polymer properties. This study also demonstrates that a support vector machine classifier could be reliably used for imposing nonlinear inequality constraints for solving dynamic optimization problems.

An Overview of the Application of Poly(lactic-co-glycolic) Acid (PLGA)-Based Scaffold for Drug Delivery in Cartilage Tissue Engineering

Poly(lactic-co-glycolic) acid (PLGA) has attracted a considerable amount of interest for biomedical application due to its biocompatibility, tailored biodegradation rate (depending on the molecular weight and copolymer ratio), approval for clinical use in humans by the U.S. Food and Drug Administration (FDA), the potential to change surface properties to create better interaction with biological materials and being suitable for export to countries and cultures where planting products with animals is unusable. For commercial use and research, PLGA has been widely studied to control small molecule drugs, proteins, and other macromolecules. This study aims to review the studies that used PLGA scaffolding and its composites as a scaffold and drug delivery in cartilage tissue engineering. It is concluded from the results that the PLGA scaffold as a synthetic scaffold, when combined with natural scaffolds or hybrids, strengthens its biological properties and performs its function better.

Synthesis of polyacrylate dispersant by DPE method and its application in inkjet ink of titanium dioxide

In this article, we synthesized a series of poly butyl acrylate-co-methacrylic acid-2-acrylamido-2-methyl propanesulfonic acid (PBAS) with different molecular weight and monomer molar ratios by 1,1-diphenylethene (DPE) method on industrial scale. The PBAS was applied as a dispersant for waterborne TiO2 paste to prepare waterborne inkjet ink. The successful synthesis of PBAS was confirmed by FTIR and 1H-NMR. To evaluate the printability and storage properties of pastes and inks, we characterized the particles, particle distribution, the storage modulus, viscosity, precipitation coefficient, and delamination height. The method creatively used in our study to characterize the printing smoothness of the ink in the industrial practical application was the filter rate of ink. We also proposed a method of using soft and hard precipitation to characterize the precipitation situation. The results of the experiment indicated that compared with commercial dispersants, PBAS5/6 had excellent performance in printing flow and anti-settling performance. This paper demonstrates the optimum dispersibility of PBAS was obtained when the molecular weight was 8500, the acid value was 100 mg KOH/g, and the 2-acrylamido-2-methylpropanesulfonic acid (AMPS) content was 20%. This fruitful work pointed out the great prospects of industrial synthetic water-based dispersants.

Breakup Behaviors of Viscoelastic Polymer Droplets in 3-D Pore Throat Structure Microchannel

Polymer solution has extremely extensive applications in many natural and industrial processes, especially in oilfield development field, such as polymer flooding, fracturing and water shut-off. Thus, the study of flow behaviors of polymer in formation pores is significantly important. In this paper, the flow behaviors of the polymer droplets in the 3-D pore throat structure were systematically studied. Additionally, the influencing factors (polymer concentration, molecular weight and pore throat ratio, for instance) were investigated. As the increasing of polymer concentration and molecular weight, the polymer droplets were more difficult to break, which means the critical flow rate decreased and the average sizes of the first daughter droplets (FDD) were longer synchronously. Moreover, with the increase in pore throat ratio, the critical flow rate increased and the length of the FDD decreased. In addition, the prediction models of the length of the FDD with polymer concentration and pore throat ratio were established, respectively. The prediction model revealed that the length of the FDD satisfied an exponential relationship with the polymer concentration and a linear relationship with the pore throat ratio. Finally, the average size of droplets after macroscopic core flooding experiment was 8 μm and 17 μm when the polymer concentration was 0.01% and 0.1%, respectively. The results were consistent with the breakup behaviors of polymer droplets in the microscopic pore throat structure.

Green Composites Based on PLA and Agricultural or Marine Waste Prepared by FDM.

Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic with low cost and ecofriendly natural fillers, without significantly modifying the processability and the mechanical performance of the neat matrix; at the same time, an increase of surface hydrophilicity was found, with possible positive influence on the biodegradability of such materials after disposal.

Heavy Metal Content and Physico-Chemical Analyses of Soils under the Litter of some Medicinal Taxa in the Luki Biosphere Reserve, Democratic Republic of the Congo

Aim: The aim of this study was to compare the texture, mineral element and heavy metal content of the soil under the litter of different selected species in relation to the plan of their pedogenesis.
 Methods: The granulometric analysis of the various samples based on laser diffraction, measurements of Total Nitrogen and Total Organic Carbon were performed using the Elemental Analyzer, the Organic Matter content is estimated by the loss of ignition method using a Salvis furnace, In order to estimate the CaCO3 content. The same samples were heated in the oven at 1000°C for 60 minutes and reweighed. The carbonate content is estimated by the loss in mass during this second firing, multiplied by 2.274 which is the molecular weight ratio between CaCO3 and CO2. The heavy metal and mineral composition was evaluated by ICP-AES and AAS.
 Results: The granulometric analyses show a sandy texture, according to the FAO classification. The organic matter content thus observed in the soils under the litter of these four species did not show any significant difference. The concentration of major mineral elements recorded in soils under the litter of Blighia welwitchii, Oncoba welwitschii, Zanthoxylum gilletii and Harungana madagascariensis did not show any significant difference. However, potassium, phosphorus, and magnesium have a high concentration compared to calcium and sodium. This study showed that the levels of cadmium, lead, arsenic and aluminum in the various samples of litter soils of all plant species including nickel for B. welwitschii are above the standards set by the Canadian Council of Ministers of the Environment for soil quality. Pollution factors for aluminum are the highest. This indicates that aluminum is the most polluting metal. The low pollution factors for lead and nickel are due to the low fixation of these metals by soils.
 Conclusions: Our study took place in the Luki Biosphere reserve and showed that the different soils under litter are polluted by very toxic and persistent heavy metals such as cadmium, lead, aluminum, arsenic and nickel. This study has revealed new aspects of heavy metal pollution. This pollution represents a serious threat to the environment in general and to humans in particular through the food chain.

Behavior of semolina, hard, soft wheat flour dough at different aging times and temperatures through LAOS properties and molecular interactions of proteins

Changes in large amplitude oscillatory shear (LAOS) were used to compare the dough strength and resilience during aging at 4 °C and 25 °C for hard wheat soft wheat and semolina (from durum wheat) flour doughs (from t = 0 to t = 108h). All dough samples aged at 25 °C showed a transition from strain stiffening to strain softening behavior. The critical strain was highest for semolina dough which showed the most solid-like viscoelastic behavior due to the higher protein content with the best protein quality. FTIR spectra indicated that β-sheet, β-turn and α-helix structures of each dough sample were affected differently due to aging process at 4 °C and 25 °C. Aging increased β-sheet content of the protein fraction in semolina and soft wheat dough and decreased it in hard wheat dough. Aging at higher temperature caused a significant increase in α-helix structure of only hard wheat dough sample while a decrease in β-turn structures of hard and soft wheat dough samples. With the combined effect of aging time and temperature, high molecular weight to low molecular weight ratio (HMW/LMW) ratios decreased for all dough samples especially at room temperature compared to aging at 4 °C. • LAOS of hard, soft and SemD showed SemD to have the highest resilience during aging. • Resilience was measured using the strain dependence of G′ M and G″ M , G′ L and G″ L . • Aging at 25 °C caused a sharp transition from strain stiffening to strain softening. • HWD and SWD had reverse trends in secondary structures of proteins, Sem stayed constant. • SDS-PAGE results showed that glutenin break down was highest in Sem dough.

Physicochemical and geroprotective comparison of Nostoc sphaeroides polysaccharides across colony growth stages and with derived oligosaccharides

Nostoc sphaeroides is a cyanobacterium traditionally used as food and medicine in the form of macrocolonies, the main supporting matrix of which is polysaccharides. Despite recent success in industrial-scale culture of colonial N. sphaeroides, biochemical and biofunctional information on the polysaccharides during colony production is lacking. Using a size-based colony growth profiling strategy, we show here that the high/low molecular weight ratio of the polysaccharides is significantly decreased while their Fourier-transform infrared absorptions remain unchanged. Importantly, monosaccharide compositions of all polysaccharides are similar to that of field colonies, indicating a comparable quality of the cultured colony products in terms of sugar composition. Subsequent experiments using free radical scavenging and Caenorhabditis elegans survival assays demonstrate both in vitro and in vivo antioxidant activities of the polysaccharides. Furthermore, the oligosaccharides prepared by partial acid hydrolysis are, like the polysaccharides, confirmed to increase oxidative survival and lifespan of C. elegans. The oligosaccharides, but not the polysaccharides, are further shown to ameliorate polyglutamine-mediated neurotoxicity and behavioral decline in a C. elegans model of proteotoxic stress, revealing their neuroprotective activity not shown by the polysaccharides. Consistently, several stress and proteostasis-associated genes are also found to be upregulated only by the oligosaccharides. Taken together, our results reveal distinct but also shared physicochemical and biofunctional properties of N. sphaeroides polysaccharides across colony growth stages and with derived oligosaccharides and also demonstrate the potentials of Nostoc oligosaccharides and thereby their parent polysaccharides as novel geroprotectors, including their beneficial effects on stress, lifespan, and age-related symptoms.

Investigating binder aging during hot in-place recycling (HIR) of asphalt pavement

Hot in-place recycling (HIR) is considered as an effective way to reuse reclaimed asphalt pavement (RAP). Heating pavement is the core technology of HIR. To ensure construction workability, the pavement should be heated and held at a relatively high temperature. However, the high heating temperature of HIR may cause significant aging on the SBS modified asphalt, which is usually used in the pavement. The objective of this study is to understand the aging behavior of SBS modified asphalt in HIR and provide appropriate guidance for future HIR projects. In this research, eight kinds of asphalt binder samples were collected and extracted from different stages of a practical HIR project. They were then tested in terms of the chemical and rheological properties. The rheological properties of asphalt are evaluated by the frequency sweep testing and Multiple Stress Creep Recovery (MSCR) testing using the Dynamic Shear Rheometer (DSR). The chemical evolution during FTIR was tracked from Fourier Transform Infrared (FTIR) spectra and Gel Permeation Chromatography (GPC). The results of the experiments showed that the influence of long-term aging is quite significant and untreated pavement exhibits much lower elastic recovery due to the degradation of SBS polymer. HIR did cause some extent of extra aging to the treated pavement, Compared with Untreated, the Carbonyl index and molecular weight ratio of polymer of Heated (#3) are reduced by 34% and 39% respectively. The effect of heating gradient between different pavement depths is noticeable. The modulus of Surface is 2.69 times that of Bottom. The PB index of Surface is 0.37 times that of Bottom. There is no noticeable chemical reaction between the rejuvenator and the aged asphalt. After adding rejuvenator, the modulus of pavement decreased by 55%.

Inverted Cylindrical Microdomains by Blending Star-Shaped and Linear Block Copolymers

We investigated the morphology formed in the binary blend of six-arm star-shaped (poly(methyl methacrylate)-block-polystyrene)6 copolymer [(PMMA-b-PS)6] and PMMA-b-PS linear diblock copolymer by varying their molecular weights as well as volume fractions of the blocks. When the molecular weight of PMMA-b-PS is much larger (> ∼4) than that of one arm of (PMMA-b-PS)6, PMMA-cylindrical microdomains are formed even though the volume fraction of PMMA (fPMMA) in both (PMMA-b-PS)6 and PMMA-b-PS is nearly symmetric (fPMMA ∼0.5). On the other hand, when the ratio of molecular weights between these two copolymers is not large, lamellar morphology is observed in the blend as expected. Very interestingly, we found that even for a binary blend with the overall volume fraction of the PMMA block (f̅PMMA) as large as 0.71, the major PMMA blocks still aggregate into cylindrical microdomains, and thus, “inverted cylinders” are formed, although PS-cylinders are observed in the neat (PMMA-b-PS)6 and PMMA-b-PS melts. This interesting inverted cylinder is mainly stabilized by two factors. On the one hand, the long linear diblock copolymer swells the domain significantly, thus preventing the short (PMMA-b-PS)6 star copolymer from forming the favorable bridging configurations in order to avoid the high stretching energy. As long as the bridging configurations are prohibited, the PMMA-core blocks of (PMMA-b-PS)6 prefer to stay inside the curvature, amplifying the tendency of forming a spontaneous curvature toward PMMA-blocks. On the other hand, the radial distribution of the long PMMA-block of the diblock and the short PMMA-block of the star increases the spontaneous curvature. The experimental results as well as the formation of the inverted cylinders have been verified by self-consistent field theory (SCFT).

PLA-based core-shell structure stereocomplexed nanoparticles with enhanced loading and release profile of paclitaxel.

Purpose: In the present study, to achieve high paclitaxel (PTX) loading in a conjugated drug delivery system with minimal long-term side effects, we formulated a novel degradable stereocomplexed micelle-like particle with a core-shell structure. Materials and methods: In this system, methoxy polyethylene glycol (MPEG) acted as the hydrophilic shell, and the stereocomplex of polylactic acid with PTX (SCPLA-PTX) acted as the hydrophobic core. The MPEG-SCPLA-PTX micelle-like particles were synthesized via the self-assembly of a MPEG-poly L-lactic acid (PLLA) copolymer with a PTX-poly D-lactic acid-PTX copolymer. The resultant copolymers and their intermediates were characterized using 1H nuclear magnetic resonance and GPC. Micelle-like particles with different molecular weight ratios of MPEG and PLLA were synthesized to demonstrate the functions of both components. Results: PTX loading into MPEG2000Da-PLLA6000Da particles reached as high as 20.11%. At 216 h, the cumulative release from MPEG5000Da-PLLA6000Da, MPEG2000Da-PLLA6000Da, and MPEG5000Da-PLLA22000Da particles were 51.5%, 37.7%, and 52.0%, respectively. Conclusions: According to the cell uptake experiments, inhibition of tumor cell growth was satisfactory, indicating that the stereocomplexed particles developed in the present study can be employed as a promising nanocarrier for PTX delivery.

Dynamic changes of structural characteristics of snow chrysanthemum polysaccharides during in vitro digestion and fecal fermentation and related impacts on gut microbiota

The in vitro simulated saliva-gastrointestinal digestion and human fecal fermentation of snow chrysanthemum polysaccharides (JHP) were investigated. Results showed that reducing sugar contents of JHP increased during the gastrointestinal digestion, and glucose released with the decrease of its molecular weight, suggesting that JHP could be partially degraded under the gastrointestinal digestion. Furthermore, after in vitro fecal fermentation, the molecular weight and molar ratio of constituent monosaccharides (galactose and galacturonic acid) of the indigestible JHP (JHP-I) significantly decreased, and both monosaccharides and oligosaccharides released, suggesting that JHP-I could be further degraded and consumed by gut microbiota. Some beneficial bacteria, such as genera Bifidobacterium, Lactobacillus, Megamonas, and Megasphaera, significantly increased, suggesting that JHP-I could change the composition and abundance of gut microbiota. These results suggest that JHP is a potential source of prebiotics, and can be helpful for better understanding of the potential digestion and fermentation mechanism of JHP.

Molecular Engineering and Morphology Control of Polythiophene:Nonfullerene Acceptor Blends for High‐Performance Solar Cells

AbstractWith the advances in organic photovoltaics (OPVs), the development of low‐cost and easily accessible polymer donors is of vital importance for OPV commercialization. Polythiophene (PT) and its derivatives stand out as the most promising members of the photovoltaic material family for commercial applications, owing to their low cost and high scalability of synthesis. In recent years, PTs, paired with nonfullerene acceptors, have progressed rapidly in photovoltaic performance. This Review gives an overview of the strategies in designing PTs for nonfullerene OPVs from the perspective of energy level modulation. A survey of the typical classes of nonfullerene acceptors designed for pairing with the benchmark PT, i.e., poly(3‐hexylthiophene) (P3HT) is also presented. Furthermore, recent achievements in understanding and controlling the film morphology for PT:nonfullerene blends are discussed in depth. In addition to the effects of molecular weight and blend ratio on film morphology, the crucial roles of miscibility between PT and nonfullerene and processing solvent in determining film microstructure and morphology are highlighted, followed by a discussion on thermal annealing and ternary active layers. Finally, the remaining questions and the prospects of the low‐cost PT:nonfullerene systems are outlined. It is hoped that this review can guide the optimization of PT:nonfullerene blends and advance their commercial applications.

Response Surface Methodology for Statistical Optimization of Chitosan/Alginate Nanoparticles as a Vehicle for Recombinant Human Bone Morphogenetic Protein-2 Delivery.

PurposeIn this study, chitosan/alginate nanoparticles are prospected as a carrier for controlled release of recombinant human bone morphogenetic protein-2 (rhBMP-2).Materials and MethodsThe rhBMP-2-loaded chitosan/alginate nanoparticles (Cs/Alg/B NPs) were prepared using the ionic gelation (IG) method. The current research was conducted to optimize the effective factors for entrapping rhBMP-2 in Cs/Alg NPs using response surface methodology (RSM) and the Box–Behnken design (BBD). The variables were the Cs/Alg molecular weight (Mw) ratios (1–3), pH (4.8–5.5), stirring rates (900–1300 rpm) and the responses included size, ζ-potential, polydispersity index (PDI), loading efficacy (LE), cumulative release (CR), and morphological degradation time (MDE). Then, the morphological properties of optimum formulation were studied for post-characterization. In the next step, the MTT assay for the optimized run was done for 24 and 48 hours.ResultsThe results revealed that the optimum conditions for the mentioned variables were stirring rate=1100 rpm, pH=5.15, and Cs/Alg Mw ratio=1.75 based on numerical optimization. It was shown that the average particle size and loading efficacy at optimum conditions were 253 nm and 67%, respectively. Other responses were as follows: CR=66%, ζ-potential=+35mV, PDI=0.5, and MDT=7 days.ConclusionThe results have suggested that the statistical optimization of rhBMP-2 offers the possibility of preparing Cs/Alg/B NPs with a favorable size, controlled release characteristics, and high loading efficiency. It is expected that the acquired optimum conditions will be useful for efficient rhBMP-2 delivery.

Determination of hydrocarbon sources in major rivers and estuaries of peninsular Malaysia using aliphatic hydrocarbons and hopanes as biomarkers

In this study, levels and sources of aliphatic hydrocarbons and hopanes in surface sediments collected from rivers and estuaries of Peninsular Malaysia were assessed. The concentrations of total n-alkanes ranged from 21.19 to 364.54, and the concentrations of hopanes ranged from 0.23 to 2.45 mg kg−1 dry weight. Evaluation of aliphatic diagnostic indices including Carbon Preference Index (CPI), low molecular weight/high molecular weight ratio (LMW/HMW), terrigenous to aquatic ratio (TAR), carbon preference index (CPI), average chain length (ACL) and pristine to phytane indicate mostly petrogenic input especially in estuaries, which is indicative of anthropogenic activities in the study areas. The results also indicate biogenic origin n-alkanes masked by the anthropogenic features in some stations. The hopane ratios indicate hopanes from the Prai and Malacca Rivers were similar to Middle East Crude Oil (MECO), indicating MECO as one of the sources of petroleum hydrocarbons.

Characteristics of indoor and personal exposure to particulate organic compounds emitted from domestic solid fuel combustion in rural areas of northwest China

Household solid fuel combustion for heating in winter is a substantial source of air pollution in rural areas of northwest China. The present study investigated the concentration characteristics and health risks of particulate matter (PM) and its organic compounds, including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs), and phthalate esters (PAEs). Indoor air and housewives' personal exposure (PE) samples were collected in Guanzhong Basin, among rural households relying on various solid fuels for heating in winter. Indoor PM primarily comprised fine PM (PM2.5, 76%), and its organic compounds were identified in particular abundance in households that used coal as the only domestic fuel (Group C, 96% in PM2.5). The mean concentration of PE to PM2.5 was 307 ± 120 μg·m−3, which was 2.4-times higher than the indoor concentration (130 ± 103 μg·m−3) because of the housewives' short-term exposure to high-concentration pollution emitted by solid fuel combustion. Organic compounds exhibited the same pattern, with PE samples having a 44% higher concentration than indoor samples. The correlation of PM2.5-bound organics between indoor and PE samples in Group C (R2 = 0.9) was higher than that in the group using coal and biomass (Group M, R2 = 0.6), indicating the stronger correlation of single-fuel heating method. The PE/indoor ratio of high molecular weight (HMW) PAHs in Group C (2.5) was higher than that of the other organic compounds (1.3) because HMW PAHs emitted through coal combustion had a larger effect on PE. This further led to higher incremental lifetime cancer risks (ICLRs) via inhalation pathway among housewives in Group C (2.4- and 1.2-times higher risk for PAHs and PAEs, respectively) than among those in Group M. However, inhalational ILCR values of Group M were still 2.1–340-times higher than the international safety standard (10−6). Therefore, the upgradation of domestic fuels and heating ways is urgently needed in rural area of northwest China to reduce indoor air pollution and health risks.

Rheological analysis of the interplay between the molecular weight and concentration of hyaluronic acid in formulations of supramolecular HA/FmocFF hybrid hydrogels

In this report, we evaluated the interplay between molecular weight and mass ratio of polymer during development of viscoelastic properties in HA/FmocFF hybrid supramolecular hydrogels. Rheology was the main tool to assess this complex relationship and the kinetics of network formation during self-assembly were correlated with inherent material properties. Formation of long-rang elastic interactions, ductility and plastic flow were strongly dependent on both size and concentration of polymer, providing a convenient application window to tune the flow properties of the hybrid hydrogels according to the intended application.

The ratio of refractive index and molecular weight of copolymers of n-butyl acrylate and styrene obtained by the method of RAFT-radical polymerization

The kinetic and molecular weight characteristics of the copolymers of n-butyl acrylate and styrene (95: 5 wt.%) obtained by the method of radical polymerization with reversible chain transfer were studied. The dependence of the refractive index on the molecular weight of the copolymers of n-butyl acrylate and styrene is shown.

Topological catenation induced swelling of ring polymers revealed by molecular dynamics simulation

Equilibrium conformational properties of a ring polymer (named by ‘inner ring’) simultaneously concatenated with a varying number of outer rings in a ‘flower’-shaped polymer catenane are explored by molecular dynamics simulations. Two different cases have been considered. In Case I, the excluded volume interactions between the outer rings are absent in a polymer catenane, while they are present in Case II. Results demonstrate that, compared to an isolated ring polymer, size and shape properties of the same, inner ring in a polymer catenane can be greatly modified by the catenation topology in both Cases. It is concluded that the topological catenation can induce a swelling of the inner ring in a catenane compared to the same ring in isolation. Importantly, scaling relationships between the swelling degree, fsw, of the inner ring and number of the outer rings, n, have been established in both Case I and Case II, fsw=anα, where the prefactor a and scaling exponent α are all predominantly dependent on molecular-weight ratio of the inner to outer rings in catenane. Besides, swelling of inner ring in a catenane of Case II is more pronounced than the same inner ring in a catenane of Case I. The mean asphericity of the inner ring is slightly increased due to the catenation topology, while its mean prolateness is remarkably modified by the catenation topology. The inner ring in a catenane becomes more oblate, compared to the same ring in isolation, with increasing either number or molecular weight of the outer rings in the catenane. Profiles of the mean prolateness changes of the inner ring from those of the same isolated ring with respect to number of the outer rings are also mainly controlled by the molecular-weight ratio of the inner to outer rings.

Early Palaeogene Climate Variability Based on n-alkane and Stable Carbon Isotopic Composition Evidenced from the Barsingsar Lignite-bearing Sequence of Rajasthan

Abstract The assessment of variations and the reconstruction of palaeoclimate, based on the distribution of n-alkanes and stable carbon isotope data, during early Palaeogene have been made on the Barsingsar lignite-bearing sequence associated with Palana Formation (Bikaner-Nagaur basin). The distribution pattern of various n-alkanes and the derived indices/ratios have widely been used as palaeoclimate indicators in several depositional realms. The distribution of n-alkanes in the studied sequence varies from C13 to C34. The values of calculated n-alkane parameters range from 26.20-28.39 (aliphatic chain length (ACL) index); 0.32-7.21 (low-to-higher molecular weight (L/H) ratio); 0.42-0.85 (Proxy wax (Pwax)); 0.20-0.67 (Proxy aqueous (Paq)); 0.28-5.22 (terrigenous/aquatic ratio (TAR)); 0.16-0.79 (C23/C29 ratio); 1.14-6.31 (C27/C31 ratio) and 1.47-7.02 (C29/C31 ratio). The δ13C varies from −24.8 to −26.1‰ and the TOC varies from 9.6 to 69.5 wt.%. All these variations indicate the changes in palaeo-climate from dry and warm to cool and wet conditions during the deposition of this lignite-bearing sequence. Further, it is also suggested that the climatic condition was cooler than that of the Palaeocene-Eocene thermal maximum (PETM) event.