Heterogeneous Polymerization Research Articles

Aqueous RAFT polymerization-induced self-assembly (PISA): amphiphilic macroRAFT self-assembly vs. monomer droplet nucleation (miniemulsion polymerization)

The effect of monomer droplet size on the particle formation mechanism in aqueous heterogeneous polymerization using a hydrophilic macroRAFT agent has been investigated.

A review on lignin based nanocomposites: Fabrication, characterization and application

Polymer Composite material is made of two or more constituent materials that, when combined, produce a material with properties that are distinct from those of the individual constituents. The fabrication of polymer nanocomposites especially lignin-based nanocomposites are growing prospective research interest, thanks to various advancements made possible by the combination of a polymeric matrix with, in most cases, an inorganic nonmaterial. The advancement and modification of lignin-based nanocomposites is a step towards the replacement of conventional plastics (traditional polymer). Polymer composites have been produced or formed specifically for a variety of applications that are employed in a specific location for a specific purpose. Lignin is a highly heterogeneous polymer that is found naturally in plants that account for up to 15–35% of woody biomass made up of several precursors. Lignols that crosslink in a variety of ways with antioxidant property, high thermal stability, biodegradability, and UV absorption characteristics. Despite the fact that lignin is the most prevalent phenolic component in nature, and a small percentage of lignin removed by industrial processing which gets turned into dispersants and fillers has the potential to enhance various properties like mechanical, thermal, thermo-chemical, anticorrosive, flame retardant and many more of the polymer composite which is beneficial for our society as well our environment.

Organic porous heterogeneous composite with antagonistic catalytic sites as a cascade catalyst for continuous flow reaction.

One-pot cascade catalytic reactions easily allow the circumvention of pitfalls of traditional catalytic reactions, such as multi-step syntheses, longer duration, waste generation, and high operational cost. Despite advances in this area, the facile assimilation of chemically antagonistic bifunctional sites in close proximity inside a well-defined scaffold via a process of rational structural design still remains a challenge. Herein, we report the successful fusion of incompatible acid-base active sites in an ionic porous organic polymer (iPOP), 120-MI@OH, via a simple ion-exchange strategy. The fabricated polymer catalyst, 120-MI@OH, performed exceedingly well as a cascade acid-base catalyst in a deacetylation-Knoevenagel condensation reaction under mild and eco-friendly continuous flow conditions. In addition, the abundance of spatially isolated distinct acidic (imidazolium cations) and basic (hydroxide anions) catalytic sites give 120-MI@OH its excellent solid acid and base catalytic properties. To demonstrate the practical relevance of 120-MI@OH, stable millimeter-sized spherical composite polymer bead microstructures were synthesized and utilized in one-pot cascade catalysis under continuous flow, thus illustrating promising catalytic activity. Additionally, the heterogeneous polymer catalyst displayed good recyclability, scalability, as well as ease of fabrication. The superior catalytic activity of 120-MI@OH can be rationalized by its unique structure that reconciles close proximity of antagonistic catalytic sites that are sufficiently isolated in space.

Preparation and characterization of paper-based high barrier material based on heterogeneous graft polymerization

Preparation and characterization of paper-based high barrier material based on heterogeneous graft polymerization

Microenvironment Modulation of Metal-Organic Frameworks (MOFs) for Coordination Olefin Oligomerization and (co)Polymerization.

The majority of commercial polyolefins are produced by coordination polymerization using early or late transition metal catalysts. Molecular catalysts containing these transition metals (Ti, Zr, Cr, Ni, and Fe, etc.) are loaded on supports for controlled polymerization behavior and polymer morphology in slurry or gas phase processes. Within the last few years, metal-organic frameworks (MOFs), a class of unique porous crystalline materials constructed from metal ions/clusters and organic ligands, have been designed and utilized as excellent supports for heterogeneous polymerization catalysis whose high density and uniform distribution of active sites would benefit the modulations of molecular weight distributions of high-performance olefin oligomers and (co)polymers. Impressive efforts have been made to modulate the microenvironment surrounding the active centers at the atomic level for improved activities of MOFs-based catalysts and controlled selectivity of olefin insertion. This review aims to draw a comprehensive picture of MOFs for coordination olefin oligomerization and (co)polymerization in the past decades with respect to different transition metal active centers, various incorporation sites, and finally microenvironment modulation. In consideration of more efforts are needed to overcome challenges for further industrial and commercial application, a brief outlook is provided.

Persimmon tannin-propane-melamine-zirconium as a bio-based organocatalyst polymer for the Knoevenagel condensation

To achieve the aims of green chemistry, persimmon tannin-propane-melamine-Zirconium (PT-Pr-Me-Zr) was synthesized as a bio-based bifunctional heterogeneous catalyst polymer. Persimmon tannin was used as a biopolymer for the synthesis of bio-organic catalyst, and the properties of PT-Pr-Me-Zr were characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, Energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. The as-synthesized composite was applied for the Knoevenagel condensation between aromatic aldehyde derivatives and malononitrile, then the conditions of reaction such as solvent and catalyst loading amount were optimized. The bifunctional property of PT-Pr-Me-Zr catalyst was improved the yield and rate of Knoevenagel reaction. The PT-Pr-Me-Zr can be recovered for five times, which was illustrated the reusability of catalyst. Based on the findings, the PT-Pr-Me-Zr can be applied as an inexpensive and ecofriendly catalyst in organic reaction such as Knoevenagel condensation.

Structural Investigation of DHICA Eumelanin Using Density Functional Theory and Classical Molecular Dynamics Simulations

Eumelanin is an important pigment, for example, in skin, hair, eyes, and the inner ear. It is a highly heterogeneous polymer with 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) building blocks, of which DHICA is reported as the more abundant in natural eumelanin. The DHICA-eumelanin protomolecule consists of three building blocks, indole-2-carboxylic acid-5,6-quinone (ICAQ), DHICA and pyrrole-2,3,5-tricarboxylic acid (PTCA). Here, we focus on the self-assembly of DHICA-eumelanin using multi-microsecond molecular dynamics (MD) simulations at various concentrations in aqueous solutions. The molecule was first parameterized using density functional theory (DFT) calculations. Three types of systems were studied: (1) uncharged DHICA-eumelanin, (2) charged DHICA-eumelanin corresponding to physiological pH, and (3) a binary mixture of both of the above protomolecules. In the case of uncharged DHICA-eumelanin, spontaneous aggregation occurred and water molecules were present inside the aggregates. In the systems corresponding to physiological pH, all the carboxyl groups are negatively charged and the DHICA-eumelanin model has a net charge of -4. The effect of K+ ions as counterions was investigated. The results show high probability of binding to the deprotonated oxygens of the carboxylate anions in the PTCA moiety. Furthermore, the K+ counterions increased the solubility of DHICA-eumelanin in its charged form. A possible explanation is that the charged protomolecules favor binding to the K+ ions rather than aggregating and binding to other protomolecules. The binary mixtures show aggregation of uncharged DHICA-eumelanins; unlike the charged systems with no aggregation, a few charged DHICA-eumelanins are present on the surface of the uncharged aggregation, binding to the K+ ions.

Energy transfer photocatalyst enabled by covalent organic framework induced reversible complexation-mediated polymerization under white LED light irradiation and the mechanism study

Heterogeneous photocatalytic polymerization has emerged as a successful method for the development of greener reversible deactivation radical polymerization protocols. In this article, a halogen-free covalent organic framework (1,3,6,8-tetrakis(4-aminophenyl) pyrene-1,3,6,8-tetrakis(4-formylphenyl) pyrene-covalent organic framework [TAPPy-TFPPy-COF]) based on imine bonds was prepared, which mediated reversible complexation-mediated polymerization of methacrylates for the synthesis of various polymers with controllable molecular weight and relatively uniform distribution under white light-emitting diode light irradiation. TAPPy-TFPPy-COF absorbed the energy from photo and was transformed to excited state (COF•), and then the energy transfer occurred between COF• and initiator 2-iodo-2-methylpropionitrile (CP-I), which cleaved the carbon-iodine bond of CP-I to generate carbon radicals, thereby initiating the polymerization reaction. The density function theory calculation suggests that the coordination of iodine of CP-I with nitrogen on TAPPy-TFPPy-COF significant decrease the bond dissociation energy, making the polymerization more efficiency. The monomer conversion and reaction time showed a linear kinetic relationship of first order. The number average molecular weight of the obtained polymers increased along with the monomer conversion rate, and in good agreement with theoretical molecular weight, indicating a high frequency of the activation-deactivation cycle. The obtained polymer has high chain end fidelity, which can be used to synthesize various block copolymers. This work provided a new direction for the development of heterogeneous catalysts for reversible complexation-mediated polymerization.

Ionic Liquid Facilitated Solvent‐Phase Polymerization of Ultrasmooth Coatings of Polycatecholamines

AbstractMussel‐inspired polycatecholamine coatings and films have proven to be versatile materials for surface modification. However, the progress of chemically modified coatings with tailored properties has been slow due to the lack of definitive evidence of their polymeric structure. Polycatecholamines form aggregates during polymerization, and their formation mechanism has been a subject of debate owing to their insolubility in traditional molecular solvents. Exploiting the capability of ionic liquids (ILs) to exhibit strong electrostatic interactions, herein, the first solution‐phase polymerization approach is reported to achieve polymerization of four catecholamines – dopamine (DA), norepinephrine (NE), L‐3,4‐dihydroxyphenylalanine (L‐DOPA), and adrenaline (AD). Kinetic control over the polymerization process in the solution phase enabled it to follow the process with 1H NMR spectroscopy, revealing the formation of structural features of resulting complex heterogeneous and soluble polymers. The polymers are both covalent and associative in nature. Solution phase polymerization prevented the formation of large aggregates in the solution, thus facilitating the formation of coatings that are ultra‐smooth and have root mean square roughness of the order of sub‐nm to nm scale.

Photoinduced Initiation of Olefin Polymerization: Enabling Spatial Control with Light.

Polyolefins constitute the majority of plastics produced worldwide. Despite the variety of precatalyst activation mechanisms known in the literature, the development of spatially controlled olefin polymerizations remains relatively unknown. If successful, control over the olefin polymerization process could provide unprecedented synthetic control and potentially broaden industrial applications. Herein, we demonstrate a simple olefin polymerization methodology termed photoinduced initiation of olefin polymerization (PIOP), wherein photoacid generators are used in conjunction with controlled irradiation to achieve precatalyst activation and olefin polymerization. These results demonstrate that PIOP can be used for solution-based polymerizations of ethylene and α-olefins and may be extended to heterogeneous polymerizations of gaseous ethylene and propylene, thereby achieving spatial control over the olefin polymerization process.

Ternary system of TiO2 confined chitosan–polyaniline​ heterostructure photocatalyst for the degradation of anionic and cationic dyes

Herein, report the preparation of TiO 2 tethered chitosan–polyaniline​ composite (TiO 2 @CS–PANI) by heterogeneous chemical polymerisation​ technique. The crystallographic, morphological and optical properties of the fabricated TiO 2 @CS–PANI composite was described with the aid of powder X-ray diffraction (PXRD), Fourier transform infra red (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) and thermogravimetry-differential scanning calorimetric (TGA-DSC) analysis. The diffuse reflectance spectra (DRS) evaluation confirmed that the TiO 2 @CS–PANI band gap was reduced compared to that of TiO 2 from 3.2 eV to 2.98 eV. The prepared photocatalyst was utilised for the degradation of toxic Methylene Blue (MB) and Methyl Orange (MO) dye molecules from water in visible light photocatalysis, and is studied in detail. The initial dye concentration of 30 mg/L and photocatalyst dosage of 100 mg were used to investigate the degradation capacity of the composite. The TiO 2 @CS–PANI composite shows extreme degradation efficiency of 92.3% and 89.5% towards MB and MO dyes, respectively. The photocatalyst offers an improved reusability up to five successive cycles. The results established that the TiO 2 @CS–PANI composite could be used as an effective photocatalyst to mineralise toxic dye molecules containing water/wastewater. • A heterogeneous chemical polymerisation method was adopted for the preparation of TiO 2 @CS-PANI photocatalyst. • The band gap of the composite was found to be 2.98 eV. • The composite exhibited high efficiency for the degradation of MB and MO dyes. • The hydroxyl radical was engaged as the primary reactive species. • The stability and reusability performance of the composite was established.

Optimization of Processing Conditions and Mechanical Properties for PEEK/PEI Multilayered Blends.

The goal of producing polyetheretherketone/polyetherimide (PEEK/PEI) blends is to combine the outstanding properties that both polymers present separately. Despite being miscible polymers, it is possible to achieve PEEK/PEI multilayered blends in which PEEK crystallinity is not significantly inhibited, as opposed to conventional extruding processes that lead to homogeneous mixtures with total polymer chain interpenetration. This study investigated a 50/50 (volume fraction) PEEK/PEI multilayered polymer blend in which manufacturing parameters were tailored to simultaneously achieve PEEK-PEI adhesion while keeping PEEK crystallinity in order to optimize the mechanical properties of this heterogeneous polymer blend. The interface adhesion was characterized with the use of three-point bending tests, which proved that a processing temperature below the melting point of PEEK produced weak PEEK-PEI interfaces. Results from differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and X-ray diffraction analysis (XRD) showed that under a 350 °C consolidation temperature, there is a partial mixing of PEEK and PEI layers in the interface that provides good adhesion. The thickness of the mixed homogeneous region at this temperature exhibits reduced sensitivity to processing time, which ensures that both polymers essentially remain separate phases. This also entails that multilayered blends with good mechanical properties can be reliably produced with short manufacturing cycles. The combination of mechanical performance and potential joining capability supports their use in a wide range of applications in the automotive, marine, and aerospace industries.

Digital Selective Reversible Phase Control of Monolithically Integrated Heterogeneous Piezoelectric Polymer for Frequency Dependent Unimorph

AbstractThanks to spontaneous polarization in molecular structure, piezoelectric polymer, poly(vinylidene fluoride) (PVDF) holds great potential for diverse applications such as organic memory and electromechanical devices. However, the transformation of PVDF into a highly polarized β‐phase has still relied on conventional processes such as repeated mechanical strain, high‐temperature heat treatment, and high‐voltage electric poling, which are time‐consuming and can potentially cause undesired damages. Here, an ultrafast and reversible digital patterning process to transform the polymorphic phase of the PVDF has been developed using the interaction of laser with molecular structure. Plasmonic gold nanoparticles realize the interaction between PVDF and laser by increasing the absorption of the laser and amplifying its characteristics. The parameters of the laser process for phase conversion are designed under the theoretical background based on molecular dynamics (MD) simulation, and through this, the process is able to freely convert phases by simple parameter modifications. The selective laser process enables a monolithically integrated heterogeneous phase of PVDF which is not allowed in conventional single‐phase producing processes. Moreover, a practical soft robot that can control its direction has been developed by utilizing the difference in mechanical responses of each phase to the electric field in a monolithically integrated single functional layer.

Genomic insights into the metabolic potential of a novel lignin-degrading and polyhydroxyalkanoates producing bacterium Pseudomonas sp. Hu109A

Lignin is the most abundant heterogeneous aromatic polymer present on planet Earth and is recalcitrant to degradation due to its complex structure, therefore, imposing a challenge to biorefinery procedures. Identifying new microbial strains with the potential to valorize lignin into useful compounds is indispensable to achieving green sustainable consumption. In this study, a novel Pseudomonas strain designated as Hu109A was isolated from the termite gut and the genome was sequenced and analyzed further. The genome contains a circular chromosome with the size of 5,131,917 bp having a GC content of 62.6% and 4698 genes. Genome annotation reveals that the strain possesses lignin-oxidizing enzymes such as DyP-type peroxidases, laccase, dioxygenase, and aromatic degradation gene clusters. The genome also contains O-methyltransferases which function in accelerating the lignin degradation by methylating the free hydroxyl phenolic compounds which in high concentration can inhibit the lignin peroxidase. Furthermore, the genome exhibits two gene clusters encoding the enzymes related to polyhydroxyalkanoates (PHA) synthesis. Pseudomonas strains are generally assumed to produce medium chain length PHAs (mcl-PHAs) only, however, strain Hu109A contains both Class II PHA synthase genes involved in mcl-PHAs and Class III PHA synthase gene involved in short-chain length PHAs (scl-PHAs). Gas Chromatography-Mass Spectrometry (GC-MS) analysis showed that using 1 g/L lignin as the sole carbon source, the maximum production of PHA observed was 103.68 mg/L, which increased to 186 mg/L with an increase in lignin concentration to 3 g/L. However, PHA production while using glucose as the sole carbon source was significantly lower than the lignin source, and maximum production was 125.6 mg/L with 3 g/L glucose. The strain Hu109A can tolerate a broad range of solvents including methanol, isopropanol, dimethylformamide, and ethanol, revealing its potential for industrial applications.

Stretchable Heterogeneous Polymer Networks of High Adhesion and Low Hysteresis.

Adhesives are ubiquitous, but the mutual exclusion between hyperelasticity and adhesiveness impedes their uses in emerging techniques such as flexible/stretchable electronics. Herein, we propose a strategy to synthesize hyperelastic adhesives (HEAs), by designating hyperelasticity and adhesiveness to the bulk and the surface of a polymer network, respectively. The bulk is hyperelastic but nonadhesive, and the surface is viscoelastic but adhesive, while the HEA is hyperelastic and adhesive. We exemplify the principle by synthesizing poly(butyl acrylate) as the bulk and poly(butyl acrylate-co-isobornyl acrylate) as the surface. The resulting HEA exhibits a low hysteresis of 4% at 100% strain and an adhesion energy of 270 J m-2. Moreover, the HEA is optically transparent, thermally stable, spontaneously adhesive to various materials, and mechanically stable against cyclic load, relaxation, and creep. We demonstrate two applications enabled by the unique combination of hyperelasticity and adhesiveness. The proposed strategy is generic, paving new avenues for stretchable yet resilient adhesives for diverse applications.

Melanin of fungi: from classification to application.

Melanin is a secondary metabolite composed of complex heterogeneous polymers. Fungal melanin is considered to be a sustainable and biodegradable natural pigment and has a variety of functional properties and biological activities. On one hand, due to its own specific properties it can play the role of antioxidant, anti-radiation, adsorption, and photoprotection. On the other hand, it has good biological activities such as hepatoprotective effect, hypolipidemic effect and anti-cancer. Therefore, it is widely used in various fields of daily life, including dyeing, food, biomedical and commercial industry. It is conducive to environmental protection and human health. However, the insolubility of fungal melanin in water, acids and organic solvents has been an obstacle to its commercial applications. Thus, the chemical modification methods of fungal melanin are summarized to increase its solubility and expand the application fields. Although fungal melanin has been used in many industries, as the structure and function of fungal melanin and modified melanin are further studied, more functional properties and bioactivities are expected to be discovered for a wide range of applications in the future.

Dynamics of Polymer Chains in Poly(ethylene oxide)/Silica Nanocomposites via a Combined Computational and Experimental Approach.

The dynamics of polymer chains in poly(ethylene oxide)/silica (PEO/SiO2) nanoparticle nanohybrids have been investigated via a combined computational and experimental approach involving atomistic molecular dynamics simulations and dielectric relaxation spectroscopy (DRS) measurements. The complementarity of the approaches allows us to study systems with different polymer molecular weights, nanoparticle radii, and compositions across a broad range of temperatures. We study the effects of spatial confinement, which is induced by the nanoparticles, and chain adsorption on the polymer's structure and dynamics. The investigation of the static properties of the nanocomposites via detailed atomistic simulations revealed a heterogeneous polymer density layer at the vicinity of the PEO/SiO2 interface that exhibited an intense maximum close to the inorganic surface, whereas the bulk density was reached for distances ∼1-1.2 nm away from the nanoparticle. For small volume fractions of nanoparticles, the polymer dynamics, probed by the atomistic simulations of low-molecular-weight chains at high temperatures, are consistent with the presence of a thin adsorbed layer that exhibits slow dynamics, with the dynamics far away from the nanoparticle being similar to those in the bulk. However, for high volume fractions of nanoparticles (strong confinement), the dynamics of all polymer chains were predicted slower than that in the bulk. On the other hand, similar dynamics were found experimentally for both the local β-process and the segmental dynamics for high-molecular-weight systems measured at temperatures below the melting temperature of the polymer, which were probed by DRS. These differences can be attributed to various parameters, including systems of different molecular weights and nanoparticle states of dispersion, the different temperature range studied by the different methods, the potential presence of a reduced-mobility PEO/SiO2 interfacial layer that does not contribute to the dielectric spectrum, and the presence of amorphous-crystalline interfaces in the experimental samples that may lead to a different dynamical behaviors of the PEO chains.

Porous Polymer Films with Tunable Pore Size and Morphology by Vapor Deposition.

The fabrication of porous polymer thin films with precise thickness and morphological control through conventional solvent-based techniques is challenging. Herein, we present a fabrication method for porous polymer thin films based on chemical vapor deposition that provides control over pore size, pore morphology, and film thickness. The porous films are prepared by co-depositing crystallizable porogen molecules with cross-linked poly(glycidyl methacrylate) (pGMA) thin films, which are synthesized by initiated chemical vapor deposition (iCVD). As the porogen is deposited, it crystallizes and phase-separates from the polymer film; simultaneous polymerization of pGMA limits crystal growth, controlling the size of crystals. Using naphthalene as porogen resulted in thin films with pore sizes from 5.9 to 24.2 μm and porosities ranging from 59.4 to 78.4%. Using octamethylcyclotetrasiloxane as porogen, which is miscible with the GMA monomer, drastically reduced the pore dimensions, ranging from 14.4 to 65.3 nm with porosities from 8.0 to 33.2%. The film morphology was highly dependent on the relative kinetics of porogen crystallization, phase separation, and heterogeneous polymerization. The kinetics of these competing processes are discussed qualitatively based on nucleation theory and Cahn–Hilliard theory. Fourier-transform infrared spectroscopy confirmed the retention of the reactive epoxide functionality of glycidyl methacrylate, which can enable further chemical derivatization as required for application in optoelectronics, sensing, separations, and biomedical devices.

Ion-Boosting the Charge Density and Piezoelectric Response of Ferroelectrets to Significantly High Levels.

In contrast to molecular-dipole polymers, such as PVDF, ferroelectrets are a new class of flexible spatially heterogeneous piezoelectric polymers with closed or open voids that act as deformable macro-dipoles after charging. With a spectrum of manufacturing processes being developed to engineer the heterogeneous structures, ferroelectrets are made with attractive piezoelectric properties well-suited for applications, such as pressure sensors, acoustic transducers, etc. However, the sources of the macro-dipole charges have usually been the same, microscopic dielectric barrier discharges within the voids, induced when the ferroelectrets are poled under a large electric field typically via a so-called corona poling, resulting in the separation and trapping of opposite charges into the interior walls of the voids. Such a process is inherently self-limiting, as the reverse internal field from the macro-dipoles eventually extinguishes the microdischarges, resulting in limited density of ions and not too high overall piezoelectric performance. Here, a new method to form ferroelectrets with gigantic electroactivity is proposed and demonstrated with the aid of an external ion booster. A laminate consisting of expanded polytetrafluoroethylene (ePTFE) and fluorinated-ethylene-propylene (FEP) was prefilled with bipolar ions produced externally by an ionizer and sequentially poled to force the separation of positive and negative ions into the open fibrous structure, rendering an impressive piezoelectric d33 coefficient of 1600 pC/N─an improvement by a factor of 4 in comparison with the d33 of a similar sandwich poled with nonenhanced corona poling. The (pre)filling clearly increases the ion density in the open voids significantly. The charges stored in the open-cell structure stays at a high level for at least 4 months. In addition, an all-organic nanogenerator was made from an ePTFE-based ferroelectret, with conducting poly(3,4-ethylene dioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) coated fabric electrodes. When poled with this ion-boosting process, it yielded an output power twice that of a similar sample poled in a conventional corona-only process. The doubling in output power is mainly brought about by the significantly higher charge density achieved with the aid of external booster. Furthermore, aside from the bipolar ions, extra monopolar ions can during the corona poling be blown into the open pores by using for instance a negative ionic hair dryer to produce a unipolar ePTFE-based ferroelectret with its d33 coefficient enhanced by a factor of 3. Ion-boosting poling thus unleashes a new route to produce bipolar or unipolar open-cell ferroelectrets with highly enhanced piezoelectric response.

Extraction, quantification and characterization of lignin extracted from bamboo biomass

Lignin, a heterogeneous polymer that presents about 20–30% in lignocellulose emerged as a promising feedstock for the production of specialty chemicals. After cellulose, Lignin is the second most abundant natural polymer. Lignin is a three-dimensional, highly cross-linked macromolecule composed of three types of substituted phenols, which include coniferyl, sinapyl, and p-coumaryl alcohols having a vast number of functional groups and linkages. The properties of lignin are dependent upon the type of extraction method used. This work-study was carried out focusing on the properties of lignin extracted from bamboo (Bambusa Polymorpha) using acid treatment, alkali treatment and sequential organosolv treatment. Isolated lignins were characterized by Fourier transform infrared spectroscopy (FTIR), UV analysis, Thermogravimetric analysis (TGA) to compare thermal and chemical composition. It was found that lignin obtained from organosolv method provided the greatest yield of the various extraction methods. FTIR spectral studies showed the characteristics peaks of lignin and it was found that the bamboo lignin is unique and it is HGS type lignin. The type of extraction method used was seen to affect the thermal properties. It was found that lignin extracted from acid treatment has the greatest thermal stability and purity.