The Degree of Disorder in Hardwood Kraft Pulps Studied by Means of LODP

Håkansson, Helena; Ahlgren, Per; Germgård, Ulf

doi:10.1007/s10570-004-5840-y

Cited by 32 publications

(23 citation statements)

References 21 publications

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“…For semicrystalline polymers, lighter areas in phase images have been interpreted as crystalline domains, while darker regions are considered to be amorphous (21). Although the banding is longer than that described in the original Hess model, it is consistent with numerous reports of a leveling off degree of polymerization, LODP, for cellulose of approximately 150-200 glucose residues (22). In a crystalline domain, each glucose residue subtends 0.5 nm along the major axis so a LODP of 150-200 nm corresponds to a crystallite length of 75-100 nm, as seen in Figure 8.5.…”

Section: Preparation and Microscopic Characterization Of Cellulose Ansupporting

confidence: 82%

Cellulose and Chitin as Nanoscopic Biomaterials

Goodrich

Bhattacharya

Winter

2009

The Nanoscience and Technology of Renewable Biomaterials

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Cellulose and chitin nanoparticles were isolated from bagasse, and shrimp shells, respectively. The nanoparticles were characterized by optical, electron, and atomic force microscopy, solid-state NMR spectroscopy, and X-ray powder diffraction methods. The nanoparticles were then topochemically modified with maleate ester groups in the case of cellulose, and medium-to long-chain aliphatic esters in the case of chitin. The derivatized nanoparticles were further characterized with spectroscopic techniques and subsequently melt processed with elastomeric thermoplastics to create nanocomposites having a significant improvement in the mechanical properties relative to the neat thermoplastics. IntroductionSince the start of the 20th century, polymeric materials have begun replacing conventional materials such as wood and metals in a diverse array of industries. Today, polymers have a ubiquitous presence in our society. They are often mixed with fillers or fibers as a versatile route to fabricating advanced materials with improved thermal and mechanical properties, to form what are called polymer composites. Typically, polymer composites have greater mechanical strength and stiffness than any of their individual components, and are used in a variety of applications. Historically, polymer composites consisted of synthetic thermoset resins reinforced with inorganic filler materials like glass fiber. TheThe Nanoscience and Technology of Renewable Biomaterials Edited

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Section: Preparation and Microscopic Characterization Of Cellulose Ansupporting

confidence: 82%

Cellulose and Chitin as Nanoscopic Biomaterials

Goodrich

Bhattacharya

Winter

2009

The Nanoscience and Technology of Renewable Biomaterials

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“…The DP of cellulose from different substrates usually decreases gradually until reaching a nominal value, namely, the leveling-off degree of polymerization (LODP) throughout the course of pretreatment [91-94]. The initial DP reduction period is believed to represent the hydrolysis of the reactive amorphous region of cellulose, whereas the slow plateau rate phase corresponds to the hydrolysis of the slowly reacting crystalline fraction of cellulose [91]. Cao et al [24] observed a reduction in molecular weight of cellulose during DA pretreatment of poplar at 170°C with ~ 86% reduction of DP reached at around 27 min.…”

Section: Cellulose Structural Alterationsmentioning

confidence: 99%

Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments

Huang

et al. 2013

Biotechnol Biofuels

525

375

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The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usually suffers from the intrinsic recalcitrance of biomass owing to the complicated structure of plant cell walls. Currently, a pretreatment step that can effectively reduce biomass recalcitrance is generally required to make the polysaccharide fractions locked in the intricacy of plant cell walls to become more accessible and amenable to enzymatic hydrolysis. Dilute acid and hydrothermal pretreatments are attractive and among the most promising pretreatment technologies that enhance sugar release performance. This review highlights our recent understanding on molecular structure basis for recalcitrance, with emphasis on structural transformation of major biomass biopolymers (i.e., cellulose, hemicellulose, and lignin) related to the reduction of recalcitrance during dilute acid and hydrothermal pretreatments. The effects of these two pretreatments on biomass porosity as well as its contribution on reduced recalcitrance are also discussed.

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“…Dilute acid pretreatment results in partial cellulose hydrolysis, leads to a reduction of DP especially at high pretreatment severity, and increases the enzymatic digestibility of cellulose [25,28,32]. Interestingly, regardless the feedstock used, acid pretreatment is often reported to reduce cellulose DP to "leveling off" DP values with amorphous cellulose rapid hydrolysis at the initial phase and crystalline cellulose hydrolysis at the slow plateau phase [33][34][35][36]. For example, a recent research indicated that the reduction of DP in poplar cellulose during acid pretreatment at 170ºC reached quickly at approximately 69% within 8.5 min, but increased slowly to approximately 86% at 26.8 min [34].…”

Section: Effect Of Feedstock Quality On Pretreatment and Enzymatic Hymentioning

confidence: 99%

Impact of feedstock quality and variation on biochemical and thermochemical conversion

Aston

Lacey

et al. 2016

Renewable and Sustainable Energy Reviews

116

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The production of biofuels from lignocellulosic feedstock is attracting considerable attention in the United States and globally as a strategy to diversify energy resources, spur regional economic development and reduce greenhouse gas emissions. Because of the wide variation in feedstock types, compositions and content of convertible organics, there is a growing need to better understand correlations among feedstock quality attributes and conversion performance. Knowledge of the feedstock impact on conversion is essential to supply quality controlled, uniform and on-spec feedstocks to biorefineries. This review paper informs the development of meaningful feedstock quality specifications for different conversion processes. Discussions are focused on how compositional properties of feedstocks affect various unit operations in biochemical conversion processes, fast pyrolysis and hydrothermal liquefaction. In addition, future perspectives are discussed that focus on the challenges and prospects of addressing compositionally intrinsic inhibitors through feedstock preprocessing at regionally distributed depots. Such preprocessing depots may allow for the commoditization of lignocellulosic feedstock and realization of stable, cost-effective and quality controlled biomass supply systems.

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The Degree of Disorder in Hardwood Kraft Pulps Studied by Means of LODP

Cited by 32 publications

References 21 publications

Cellulose and Chitin as Nanoscopic Biomaterials

Cellulose and Chitin as Nanoscopic Biomaterials

Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments

Impact of feedstock quality and variation on biochemical and thermochemical conversion

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