Synthesis of Lignin-Based Thermoplastic Copolyester Using Kraft Lignin as a Macromonomer (original) (raw)
Related papers
BioResources, 2012
This work focused on providing a molecular understanding of the way the polymeric properties of kraft lignin and its derivatives are affected by various thermal treatments. This information was then correlated with the polymeric properties of the materials (glass transition temperature (T g ), molecular weight characteristics, and thermal stability) for a series of selectively and progressively derivatized softwood kraft lignin samples. Softwood kraft lignin was highly susceptible to thermally induced reactions that caused its molecular characteristics to be severely altered with the concomitant formation of irreversible cross-linking. However, by fully methylating the phenolic OH groups from within the structure of softwood kraft lignin, the thermal stability of these materials was dramatically enhanced and their T g reduced. While optimum thermal stability and melt re-cycling was observed with the fully methylated derivatives, fully oxypropylated phenolic substitution did not offer the same possibilities. The accumulated data is aimed at providing the foundations for a rational design of single component, lignin-based thermoplastic materials with reproducible polymeric properties when thermally processed in a number of manufacturing cycles.
Thermal and Mechanical Properties of Esterified Lignin in Various Polymer Blends
2021
Lignin is an abundant polymeric renewable material and thus a promising candidate for incorporation in various commercial thermoplastic polymers. One challenge is to increase the dispersibility of amphiphilic lignin in lipophilic thermoplastic polymers We altered Kraft lignin using widely available and renewable fatty acids, such as oleic acid, yielding more than 8 kg of lignin ester as a light brown powder. SEC showed a molecular weight of 5.8 kDa with a PDI = 3.80, while the Tg of the lignin ester was concluded to 70 °C. Furthermore, the lignin ester was incorporated (20%) into PLA, HDPE, and PP to establish the thermal and mechanical behavior of the blends. DSC and rheological measurements suggest that the lignin ester blends consist of a phase-separated system. The results demonstrate how esterification of lignin allows dispersion in all the evaluated thermoplastic polymers maintaining, to a large extent, the tensile properties of the original material. The impact strength of HD...
Thermal Properties of Lignin in Copolymers, Blends, and Composites; A Review
Green Chem., 2015
The need for renewable alternatives to conventional petroleum based polymers has been the motivation for work on biobased composites, blends and materials whose foundations are carbon neutral feedstocks. Lignin, an abundant plant derived feedstock, and waste byproduct of the cellulosic ethanol and pulp and paper industry, qualifies as a renewable material. Despite the fact that it is often difficult to blend lignin with other polymers due to its complex structure and reactivity, published research over the past decade, has focused on issues such as lignin miscibility with other polymers, the thermal and mechanical strength behavior of its copolymers and its fractions as well as efforts of tuning its thermal properties via chemical modifications and other means. As such this effort now attempts to offer a comprehensive overview that largely discusses the importance of these processes with the aim toward effective, cost efficient and environmentally friendly means that may allow the utilization of this important and largely ignored biopolymer.
Progress in Green Polymer Composites from Lignin for Multifunctional Applications: A Review
ACS Sustainable Chemistry & Engineering, 2014
Rising environmental concerns and depletion of petrochemical resources has resulted in an increased interest in biorenewable polymer-based environmentally friendly materials. Among biorenewable polymers, lignin is the second most abundant and fascinating natural polymer next to cellulose. Lignin is one of the three major components found in the cell walls of natural lignocellulosic materials. Lignin is widely available as a major byproduct of a number of industries involved in retrieving the polysaccharide components of plants for industrial applications, such as in paper making, ethanol production from biomass, etc. The impressive properties of lignin, such as its high abundance, low weight, environmentally friendliness and its antioxidant, antimicrobial, and biodegradable nature, along with its CO 2 neutrality and reinforcing capability, make it an ideal candidate for the development of novel polymer composite materials. Considerable efforts are now being made to effectively utilize waste lignin as one of the components in polymer matrices for high performance composite applications. This article is intended to summarize the recent advances and issues involving the use of lignin in the development of new polymer composite materials. In this review, we have made an attempt to classify different types of lignin-reinforced polymer composites starting from synthetic to biodegradable polymer matrices and highlight recent advances in multifunctional applications of lignin. The structural features and functions of the lignin/polymer composite systems are discussed in each section. The current research trends in lignin-based materials for engineering applications, including strategies for modification of lignin, fabrication of thermoset/thermoplastic/biodegradable/rubber/foam composites, and the use of lignin as a compatibilizer are presented. This study will increase the interest of researchers all around the globe in lignin-based polymer composites and the development of new ideas in this field.
Synthesis and Characterization of Lignin-grafted-poly(ε-caprolactone) from Different Biomass Sources
Bew Biotechnology, 2020
Modification of lignin with poly(ε-caprolactone) is a promising approach to valorize industrial low-value lignins and to advance the bioeconomy. We have synthesized lignin grafted poly(ε-caprolactone) (lignin-g-PCL) co-polymers via ring-opening polymerization of ε-caprolactone with different types of lignins of varying botanical sources (G-type pine lignin, S/G-type poplar lignin, and C-type Vanilla seeds lignin) and lignin extraction methods (Kraft and ethanol organosolv pulping). The lignin-g-PCL copolymer showed remarkably improved compatibility and dispersion in acetone, chloroform, and toluene in comparison to non-modified lignins. The structure and thermal properties of the lignin-g-PCL were investigated using Fourier-transform infrared spec-troscopy (FTIR), 31 P nuclear magnetic resonance (NMR), 2D heteronuclear single quantum correlation (HSQC) NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). We have found that all the technical lignins were reactive to the copolymerization reaction regardless of their plant source and isolation methods. The molecular weights of the synthesized lignin-g-PCL copolymers were positively correlated with the content of aliphatic lignin hydroxyls, suggesting that the copolymerization reaction tends to occur preferentially at the aliphatic hydroxyls rather than the phenolic hydroxyls of lignin. Thermal analyses of the lignin-g-PCL copolymers were studied, and in general, a reduction of melting temperature and crystallinity percentage in comparison to the neat PCL was observed. However, the thermal behavior of lignin-g-PCL co-polymers varied depending on the lignin feedstocks employed in the copolymerization reaction. Introduction The practical utilization of lignin from lignocellulosic biomass is critical for the accelerated development of the bioeconomy and circular carbon economy. Lignin is the second most abundant terrestrial polymer (15− 40% by weight, 40% by energy) of lignocellulosic biomass after cellulose [1]. A large quantity of lignin (~62 million tons), is generated annually from chemical pulping, and biorefining processes [1]. Lignin attracts tremendous interest due to its aromatic structure with high functional groups and carbon densities that can afford, in principle, a broad array of bio-derived chemicals, polymers, and materials. It has historically been burned for energy and chemicals recovery in the pulping industry; however, less than 2% of industrial lignin has been valorized to profitable chemicals and products, such as fillers, additives, dispersants, adhesives, surfactants, and UV blockers [2-4]. The brittle nature of lignin, along with its highly complex 3D structure and incompatibility with nonpolar polymers, raise substantial challenges to its valorization. To exploit inexpensive lignin resources into high-value polymers and composites, three types of technical approaches are generally utilized, namely (1) direct incorporation of lignin to polymer for composites; (2) chemical modification of lignin and lignin copoly-merization to generate products with novel properties; and (3) cracking
Lignin-polymer systems and some applications
Progress in Polymer Science, 1986
Lignin is a renewable, non-toxic, commercially available and low costing resource which has the potential of being utilized as a basic raw material for the chemical industry. In spite of many years of development effort however, this potential has not been fully realized. One of the many reasons for the difficulties encountered in the production of useful polymeric products is the fact that the technical processes by which lignin is obtained, alter its macromolecular structure in such a fashion as to reduce its reactivity. Recent developments of the macromolecular uses in lignin-polymer material systems have shown an increased awareness of the inherent limitations and potential of the structure of lignin. In this paper, the present state of knowledge regarding the chemical structure of lignin is briefly described, and some more current areas of application are reviewed; lignin graft copolymers, lignin-thermosetting polymer systems and lignin-elastomer systems.
Synthesis and Characterization of Poly(arylene ether sulfone) Kraft Lignin Heat Stable Copolymers
ACS Sustainable Chemistry & Engineering, 2014
In this effort we aim at documenting our understanding of using the phenolic hydroxyl groups of technical softwood kraft lignin in replacing the multifunctional phenolic component required for the synthesis of poly(arylene ether) sulfones. To do this we use a two-pronged approach that uses fractionated softwood kraft lignin whose phenolic hydroxyl groups have been systematically protected in order to avoid gelation when copolymerized with 4, 4′-diflourodiphenyl sulfone (DFDPS). This has been done by careful 31P NMR profiling of the various hydroxyl groups present in the lignin as a function of the degree of phenolic hydroxyl group protection. For all copolymers, weight average molecular weights (Mw), polydispersity indices (PDI), glass transition temperatures (Tg), and thermal stability profiles (TGA) were obtained, providing an integrated picture of the scientific and technological ramifications of this work. Overall, this effort provides the foundations for creating lignin copolym...