scholarly journals Tunable Boc Modification of Lignin and Its Impact on Microbial Degradation Rate

Author(s):  
Liuqun Gu ◽  
Meifeng Wang ◽  
Hui Li ◽  
Kai Ni Teh ◽  
Yiqun Li ◽  
...  

<p>A new type of modified lignin, lignin-p-Boc, was obtained through reaction with di-<i>tert</i>-butyl dicarbonate (Boc<sub>2</sub>O) in aqueous media catalyzed by 4-dimethylaminopyridine (DMAP). Boc modification occurred regardless of type of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate (a common byproduct from pulping industry; lignin content: 60%). Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as a potential crosslinker in design of bioresorbable composite polymeric implants. Furthermore, the effects of the modification on the breakdown rate of alkali lignin by microbes was investigated, and the results showed that the modification substantially decreases the breakdown rate. The tunable Boc modification process was designed via a system thinking, including availability of raw lignin, economical/green modification, potentiality of drop-in-change to current thermoplastic processing, modification impact on microbial degradability/disposed environment at the end of use life; hence the holistic consideration makes this alternative method for upgrade of technical lignins very practical for future industrial application. Via forming “easily breakable covalent bonds” with thermopolymers, Lignin-p-BOCs are also promising to play an important role as both excellent binders via “random match” and reductants in transforming linear plastic waste into circular plastics.</p><br>

2018 ◽  
Author(s):  
Liuqun Gu ◽  
Meifeng Wang ◽  
Hui Li ◽  
Kai Ni Teh ◽  
Yiqun Li ◽  
...  

A new type of modified lignin, lignin-p-Boc was obtained through reaction with di-<i>tert</i>-butyl dicarbonate in aqueous media. Boc modification occurred regardless of types of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate. Further reactivity of Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as potential crosslinker in design of bioresorbable composite polymeric implants. Furthermore, the effects of the modification on the breakdown rate of alkali lignin by microbial (white rot fungus <i>P. chrysosporium</i>) was investigated, and the results showed that the modification obviously decreased <a>the breakdown rate</a>.<div>A pre-recorded video of my presentation in ACS Fall National Meeting 2020 see: <a href="https://doi.org/10.1021/scimeetings.0c06672" rel="nofollow" target="_blank">https://doi.org/10.1021/scimeetings.0c06672</a></div>


2018 ◽  
Author(s):  
Liuqun Gu ◽  
Meifeng Wang ◽  
Hui Li ◽  
Kai Ni Teh ◽  
Yiqun Li ◽  
...  

A new type of modified lignin, lignin-p-Boc was obtained through reaction with di-<i>tert</i>-butyl dicarbonate in aqueous media. Boc modification occurred regardless of types of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate. Further reactivity of Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as potential crosslinker in design of bioresorbable composite polymeric implants. Furthermore, the effects of the modification on the breakdown rate of alkali lignin by microbial (white rot fungus <i>P. chrysosporium</i>) was investigated, and the results showed that the modification obviously decreased <a>the breakdown rate</a>.<div>A pre-recorded video of my presentation in ACS Fall National Meeting 2020 see: <a href="https://doi.org/10.1021/scimeetings.0c06672" rel="nofollow" target="_blank">https://doi.org/10.1021/scimeetings.0c06672</a></div>


2018 ◽  
Author(s):  
Liuqun Gu ◽  
Meifeng Wang ◽  
Hui Li ◽  
Kai Ni Teh ◽  
Yiqun Li ◽  
...  

A new type of modified lignin, lignin-p-Boc, was obtained through reaction with di-<i>tert</i>-butyl dicarbonate in aqueous media. Boc modification occurred regardless of types of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate (a common byproduct from pulping industry). Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic. Furthermore, the effects of the modification on the breakdown rate of alkali lignin by microbial was investigated, and the results showed that the modification obviously decreased <a>the breakdown rate</a>.


2015 ◽  
Vol 14 (3) ◽  
pp. 525-532 ◽  
Author(s):  
Daniela Suteu ◽  
Gabriela Biliuta ◽  
Lacramioara Rusu ◽  
Sergiu Coseri ◽  
Gabriela Nacu
Keyword(s):  

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1982
Author(s):  
Weilin Liu ◽  
Jiansan Li ◽  
Xiangqi Huang ◽  
Jinye Bi

In this study, calcium carbonate (CaCO3) microparticles having pH-sensitive properties were loaded with sodium lignosulfonate (SLS), a corrosion inhibitor. Scanning electron microscope (SEM), UV–VIS spectrophotometer (UV-vis), X-ray diffraction (XRD), and attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR) were applied to evaluate the properties of the synthetic microparticles. This material could lead to the release of corrosion inhibitor under different pH conditions of the aqueous media. However, the extent of release of the corrosion inhibitor in the acidic media was higher, leading to enhanced shielding effect of the Q235 steel. These microparticles can serve as anti-corrosion additive for epoxy resin-coated Q235 steel. Electrochemical experiments were used to assess the anti-corrosive ability of the epoxy coatings in simulated concrete pore (SCP) solution, confirming the superior corrosion inhibition of the epoxy coating via incorporation of 5 wt % calcium carbonate microparticles loaded with SLS (SLS/CaCO3). The physical properties of coating specimens were characterized by water absorption, contact angle, adhesion, and pencil hardness mechanical tests.


1963 ◽  
Vol 36 (1) ◽  
pp. 90-101
Author(s):  
Torkel Weis-Fogh

Abstract There is much circumstantial evidence in favor of the belief that elastin and some other structural proteins exist in the rubberlike state of matter (see reviews by Wöhlisch, 1939; Astbury, 1940; Meyer, 1950; Kendrew, 1954), but it will be shown that the crucial evidence from thermodynamic experiments is ambiguous. The discovery of a new type of highly elastic structural protein, resilin ( Weis-Fogh, 1960; Bailey and Weis-Fogh, 1961), made it possible to re-investigate the problem by using more suitable samples. Since the thermodynamic experiments reported here gave a clear-cut answer, it was legitimate to interpret in detail the mechanical and optical properties of resilin according to the kinetic theories of rubber elasticity and so to obtain valuable information about the molecular structure of at least one rubberlike protein (Weis-Fogh, in preparation). Resilin is the essential elastic component in certain mechanical springs in the cuticle of arthropods (cf. the Latin resilire, to spring back) and it has a number of properties which make it ideally suited for this type of investigation (Weis-Fogh, 1959; 1960). When swollen with water, it exhibits typical long-range elasticity, it is heat-stable up to 140° C, crosslinked by very stable covalent bonds and insoluble in all solvents that do not break the peptide backbone but it is easily digested by all kinds of proteolytic enzymes. Moreover, it is secreted as thick continuous layers by the epidermis in a pure form unmixed with other proteins, lipids or polysaccharides and spatially separated from chitin, the only other structural component of the rubberlike cuticle (Weis-Fogh, 1960; Bailey and Weis-Fogh, 1961). It is thus possible to obtain native resilin in the form of relatively large, homogeneous samples, 0.1 mm thick and 1 mm long. Such samples are hyaline, devoid of color, and mechanically as well as optically isotropic in all directions and at all degrees of swelling. They are also devoid of structure (light and electron microscopy), and no trace of crystallinity has been found (X-ray diffraction) even in samples that were stretched near to the breaking point and then slowly dried (Elliott, Huxley, and Weis-Fogh, in preparation). The amino acid composition is unique and different from that of elastin, elastoidin, silk fibroin and collagen, and about one third of the side chains carry polar groups (Bailey and Weis-Fogh, 1961). The rubberiness of elastin is generally thought to be intimately connected with the scarcity of polar groups (5%; cf. Lloyd and Garrod, 1946). This paper will deal with experiments that show that the elastic force of resilin is connected with entropy changes caused by deformation, as in true rubbers, rather than with changes in internal energy, as in most solids.


1970 ◽  
Vol 37 (3) ◽  
pp. 493-505 ◽  
Author(s):  
J. Garnier ◽  
B. Ribadeau Dumas

SummaryOn the basis of complete permeability by high molecular weight reagents of casein micelles in milk and a uniform distribution of the 3 different casein subunits, a model of the micelle structure is proposed. It is composed of an average repeating unit of 1 κ-, 2 αs1;- and β-casein subunits assembled in a 3-dimensional network or branched polymer made of 130–130000 monomers, in which the trimers of κ-casein occupy the nodes and the copolymers of αs1;- and β-caseins make up the branches. All the associations between subunits are through non-covalent bonds. The chemical composition varies with the number of αs1;- and β;-casein subunits in the branches. This proposed structure is strongly supported by evidence from electron microscopy and a scale model has been made. It leads to an understanding of the role of κ-casein in micelle formation and opens new perspectives in explaining some properties of the caseins. It offers an interesting example of a new type of quaternary structure of protein subunits.


Author(s):  
Fangda Cui ◽  
I. J. Rao

Shape memory polymers (SMP’s) are polymers that have the ability to retain a temporary shape, which can revert back to the original shape on exposure to specific triggers such as increase in temperature or exposure to light at specific wavelengths. A new type of shape memory polymer, light activated shape memory polymers (LASMP’s) have been developed in the past few years. In these polymers the temporary shapes are fixed by exposure to light at a specific wavelength. Exposure to light at this wavelength causes the photosensitive molecules, which are grafted on to the polymer chains, to form covalent bonds. These covalent bonds are responsible for the temporary shape and act as crosslinks. On exposure to light at a different wavelength these bonds are cleaved and the material can revert back to its original shape. A constitutive model of LASMP’s which based on the notion of multiple natural configurations has been developed (see Sodhi and Rao[1]). In this work we use this model to analyze the mechanical behavior of LASMP’s under a specific boundary value problem, namely, the problem of circular shear. We use this model problem to study the behavior of the LASMP’s when a temporary configuration is formed by exposing the polymer to light. In addition we show that these materials are able to undergo complex cycles of deformation due to the flexibility with which these temporary configurations can be formed and removed by exposure to light.


Konversi ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Rifatus Saufiyah ◽  
Lini Ingriyani ◽  
Meilana Dharma Putra

Abstrak-Surfaktan merupakan salah satu bahan baku penting didalam berbagai bidang industri, seperti: emulsifier, corrosion inhibition, foaming, detergent, dan hair conditioning. Penelitian ini bertujuan untuk mengetahui proses produksi surfaktan dari sekam padi melalui proses sulfonasi langsung. Selain itu penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi NaHSO­3 dan peningkatan suhu terhadap jumlah surfaktan. Surfaktan pada penelitian ini dibuat dari kandungan lignin sekam padi yang diperoleh dari daerah Kuin, Kalimantan Selatan. Sekam padi terlebih dahulu dijemur dan diayak. Sekam padi lolos ayakan 355 mikron dan tertahan ayakan 250 mikron dicampur dengan 250 mL natrium bisulfit (dengan variasi 10%, 15%, 20%, 25%, 30%) untuk dicek pHnya. H2SO4 ditambahkan pada larutan campuran agar pH nya menjadi 4. Larutan campuran dipanaskan pada variasi suhu 70oC, 85oC dan 100oC. Hasil reaksi disaring dan diambil 5mL filtrat untuk dioven sehingga diperoleh serbuk sodium lignosulfonat (surfaktan). Dari hasil yang didapatkan, dapat disimpulkan semakin besar konsentrasi NaHSO3 dan temperatur operasi maka kadar surfaktan akan semakin meningkat. Yield surfaktan tertinggi diperoleh pada konsentrasi larutan NaHSO3 30% dengan suhu operasi 100oC yaitu 1,19% (%berat). Hasil perbandingan uji karakteristik larutan surfaktan sekam padi dengan larutan surfaktan sintetis (ABS) menunjukkan kedua larutan berbau sulfur dan agak asam, mempunyai pH 5 dan larut sempurna dalam air. Sementara itu untuk variabel warna terdapat perbedaan dimana untuk larutan surfaktan sintetis (ABS) berwarna kuning kecoklatan dan untuk larutan surfaktan sekam padi memiliki warna kekuningan. Kata kunci: sekam padi, surfaktan, sulfonasi, sodium lignosulfonat, UV-VIS Abstract-Surfactant is one of the most important raw materials used in various industrial fields, such as emulsifiers, corrosion inhibitors, foaming agent, detergent and hair conditioning products. This study aims to find out the surfactant production process of rice husk through direct sulfonation process. In addition, this study aims to determine the effect of variation of NaHSO­3 concentrations and variation of temperature on the amount of surfactant. Surfactant in this study was made from lignin content of rice husk which was obtained from the Kuin region, South Kalimantan. Firstly, rice husk was dried and sieved. The rice husk that passed the 355 micron sieve and retained on 250 micron sieve was mixed with 250 mL of sodium bisulfite (the variations were 10%, 15%, 20%, 25% and 30%) for pH check. H2SO4 was added to the mixture to get pH 4. The mixtures then was heated at 70oC, 85oC and 100oC. The solution result was filtered, 5 mL of the solution was ovened to obtain the powder of sodium lignosulfonate (surfactant). From the results obtained, it can be concluded that the greater concentration of NaHSO3 and operating temperature, the higher the surfactant yield will be obtained. The highest yield was obtained at a concentration of surfactant NaHSO3 solution of 30% with operating temperature of 100oC is 1.19% (wt%). The comparison of characteristics test of rice husk surfactant solution with a solution of synthetic surfactant (ABS) showed two solutions with a scent of sulfur and slightly acidic, having a pH of 5 and completely soluble in water. Meanwhile, for the color variable, there is a visible difference. For the synthetic surfactant solution (ABS) the solution was brownish yellow and rice husk surfactant solution had a yellowish color. Keywords: rice husk, surfactant, sulphonated, sodium lignosulfonate, characteristics test


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