Older adults experience of transition to the community from the emergency department: a qualitative evidence synthesis.

AIM: Older adults comprise a growing proportion of Emergency Department (ED) attendees and are vulnerable to adverse outcomes following an ED visit including ED reattendance within 30 days. Interventions to reduce older adults' risk of adverse outcomes following an ED attendance are proliferating and often focus on improving the transition from the ED to the community. To optimise the effectiveness of interventions it is important to determine how older adults experience the transition from the ED to the community. This study aims to systematically review and synthesise qualitative studies reporting older adults' experiences of transition to the community from the ED. METHODS: Six databases (Academic Search Complete, CINAHL, MEDLINE, PsycARTICLES, PsycINFO, and Social Science Full Text) were searched in March 2022 and 2023. A seven-step approach to meta-ethnography, as described by Noblit and Hare, was used to synthesise findings across included studies. The methodological quality of the included studies was appraised using the 10-item Critical Appraisal Skills Programme (CASP) checklist for qualitative research. A study protocol was registered on PROSPERO (Registration: CRD42022287990). FINDINGS: Ten studies were included, and synthesis led to the development of five themes. Unresolved symptoms reported by older adults on discharge impact their ability to manage at home (theme 1). Limited community services and unresolved symptoms drive early ED reattendance for some older adults (theme 2). Although older adults value practical support and assistance transporting home from the ED this is infrequently provided (theme 3). Accessible health information and interactions are important for understanding and self-managing health conditions on discharge from the ED (theme 4). Fragmented Care between ED and community is common, stressful and impacts on older adult's ability to manage health conditions (theme 5). A line of argument synthesis integrated these themes into one overarching concept; after an ED visit older adults often struggle to manage changed, complex, health and care needs at home, in the absence of comprehensive support and guidance. DISCUSSION/ CONCLUSION: Key areas for consideration in future service and intervention development are identified in this study; ED healthcare providers should adapt their communication to the needs of older adults, provide accessible information and explicitly address expectations about symptom resolution during discharge planning. Concurrently, community health services need to be responsive to older adults' changed health and care needs after an ED visit to achieve care integration. Those developing transitional care interventions should consider older adults needs for integration of care, symptom management, clear communication and information from providers and desire to return to daily life.

Exploring stakeholders' experiences of comprehensive geriatric assessment in the community and out-patient settings: a qualitative evidence synthesis.

BACKGROUND: Comprehensive Geriatric Assessment (CGA) is a multidimensional interdisciplinary process that addresses an older adult's biopsychosocial capabilities to create an integrated and co-ordinated plan of care. While quantitative evidence that demonstrates the positive impacts of CGA on clinical and process outcomes has been synthesised, to date qualitative research reporting how older adults and service providers experience CGA has not been synthesised. This study aimed to systematically review and synthesise qualitative studies reporting community-dwelling older adults', caregivers' and healthcare professionals' (HCP) experiences of CGA in the primary care and out-patient (OPD) setting. METHOD: We systematically searched five electronic databases including MEDLINE, CINAHL, PsycINFO, PsycARTICLES and Social Sciences Full Text targeting qualitative or mixed methods studies that reported qualitative findings on older adults', caregivers' and HCPs' experiences of CGA in primary care or out-patient settings. There were no language or date restrictions applied to the search. The protocol was registered with the PROSPERO database (Registration: CRD42021283167). The methodological quality of the included studies was appraised using the Critical Appraisal Skills Programme checklist for qualitative research. Results were synthesised according to Noblit and Hare's seven-step approach to meta-ethnography, which involves an iterative and inductive process of data synthesis. RESULTS: Fourteen studies were included where CGA was completed in the home, general practice, out-patient setting in acute hospitals and in hybrid models across the community and hospital-based OPD settings. Synthesis generated four key themes: (1) CGA is experienced as a holistic process, (2) The home environment enhances CGA, (3) CGA in the community is enabled by a collaborative approach to care, and (4) Divergent experiences of the meaningful involvement of older adults, caregivers and family in the CGA process. CONCLUSION: Findings demonstrate that CGA in a home-based or OPD setting allows for a holistic and integrated approach to care for community-dwelling older adults while increasing patient satisfaction and accessibility of healthcare. Healthcare professionals in the community should ensure meaningful involvement of older adults and their families or caregivers in the CGA process. Further robustly designed and well reported trials of different models of community-based CGA informed by the findings of this synthesis are warranted.

Establishing the core elements of a frailty at the front door model of care using a modified real-time Delphi technique.

BACKGROUND: Innovations in models of care for older adults living with frailty presenting to the emergency department (ED) have become a key priority for clinicians, researchers and policymakers due to the deleterious outcomes older adults experience due to prolonged exposure to such an environment. This study aimed to develop a set of expert consensus-based statements underpinning operational design, outcome measurement and evaluation of a Frailty at the Front Door (FFD) model of care for older adults within an Irish context. METHODS: A modified real-time Delphi method was used. Facilitation of World Café focus groups with an expert panel of 86 members and seperate advisory groups with a Public and Patient Involvement panel of older adults and members of the Irish Association of Emergency Medicine generated a series of statements on the core elements of the FFD model of care. Statements were analysed thematically and incorporated into a real-time Delphi survey, which was emailed to members of the expert panel. Members were asked to rank 70 statements across nine domains using a 9-point Likert scale. Consensus criteria were defined a priori and guided by previous research using 9-point rating scales. RESULTS: Fifty members responded to the survey representing an overall response rate of 58%. Following analyses of the survey responses, the research team reviewed statements for content overlap and refined a final list of statements across the following domains: aims and objectives of the FFD model of care; target population; screening and assessment; interventions; technology; integration of care; evaluation and metrics; and research. CONCLUSION: Development of a consensus derived FFD model of care represents an important step in generating national standards, implementation of a service model as intended and enhances opportunities for scientific impact. Future research should focus on the development of a core outcome set for studies involving older adults in the ED.

Flame resistant cotton lines generated by synergistic epistasis in a MAGIC population.

Textiles made from cotton fibers are flammable and thus often include flame retardant additives for consumer safety. Transgressive segregation in multi-parent populations facilitates new combinations of alleles of genes and can result in traits that are superior to those of any of the parents. A screen of 257 recombinant inbred lines from a multi-parent advanced generation intercross (MAGIC) population for naturally enhance flame retardance (FR) was conducted. All eleven parents, like all conventional white fiber cotton cultivars produce flammable fabric. MAGIC recombinant inbred lines (RILs) that produced fibers with significantly lower heat release capacities (HRC) as measured by microscale combustion calorimetry (MCC) were identified and the stability of the phenotypes of the outliers were confirmed when the RILs were grown at an additional location. Of the textiles fabricated from the five superior RILs, four exhibited the novel characteristic of inherent flame resistance. When exposed to open flame by standard 45° incline flammability testing, these four fabrics self-extinguished. To determine the genetic architecture of this novel trait, linkage, epistatic and multi-locus genome wide association studies (GWAS) were conducted with 473k SNPs identified by whole genome sequencing (WGS). Transcriptomes of developing fiber cells from select RILs were sequenced (RNAseq). Together, these data provide insight into the genetic mechanism of the unexpected emergence of flame-resistant cotton by transgressive segregation in a breeding program. The incorporation of this trait into global cotton germplasm by breeding has the potential to greatly reduce the costs and impacts of flame-retardant chemicals.

Effectiveness of community-based multidisciplinary integrated care for older people: a protocol for a systematic review.

INTRODUCTION: The increasing number of older adults with multiple complex care needs has placed increased pressure on healthcare systems internationally to reorientate healthcare delivery. For many older adults, their first point of contact with the health service is with their general practitioner (GP) and GP participation with integrated care models is the foundation of a population-based approach. A knowledge gap remains in relation to the effectiveness of GP participation in community-based integrated health and social care approaches for older adults. This systematic review aims to examine the effectiveness of multidisciplinary-integrated care for community-dwelling older adults with GP participation. METHODS AND ANALYSIS: This systematic review will include randomised controlled trials (RCTs), quasi and cluster RCTs focusing on integrated care interventions for community-dwelling older adults by multidisciplinary teams including health and social care professionals and GPs. The databases PUBMED, EMBASE, CINAHL, Central Register of Controlled Trials in the Cochrane Library and MEDLINE will be searched. The primary outcome measure will be functional status. Secondary outcomes will include: primary healthcare utilisation, secondary healthcare utilisation, participant satisfaction with care, health-related quality of life, nursing home admission and mortality. The methodological quality of the studies will be assessed using the Cochrane Risk of Bias Tool V.2. The elements of care integration will be mapped in the individual studies using the Rainbow Model of Integrated Care taxonomy. A meta-analysis will be completed, depending on the uniformity of the data. Grading of Recommendations, Assessment, Development and Evaluation will be used to assess the certainty of evidence. ETHICS AND DISSEMINATION: Formal ethical approval is not required as all data included are anonymous secondary data. Scientific outputs will be presented at relevant conferences and in collaboration with our public and patient involvement stakeholder panel of older adults at the Ageing Research Centre at the University of Limerick. PROSPERO REGISTRATION NUMBER: CRD42022309744.

Intrafibrillar Dispersion of Cuprous Oxide (Cu2O) Nanoflowers within Cotton Cellulose Fabrics for Permanent Antibacterial, Antifungal and Antiviral Activity.

With increasingly frequent highly infectious global pandemics, the textile industry has responded by developing commercial fabric products by incorporating antibacterial metal oxide nanoparticles, particularly copper oxide in cleaning products and personal care items including antimicrobial wipes, hospital gowns and masks. Current methods use a surface adsorption method to functionalize nanomaterials to fibers. However, this results in poor durability and decreased antimicrobial activity after consecutive launderings. In this study, cuprous oxide nanoparticles with nanoflower morphology (Cu2O nanoflowers) are synthesized in situ within the cotton fiber under mild conditions and without added chemical reducing agents from a copper (II) precursor with an average maximal Feret diameter of 72.0 ± 51.8 nm and concentration of 17,489 ± 15 mg/kg. Analysis of the Cu2O NF-infused cotton fiber cross-section by transmission electron microscopy (TEM) confirmed the internal formation, and X-ray photoelectron spectroscopy (XPS) confirmed the copper (I) reduced oxidation state. An exponential correlation (R2 = 0.9979) between the UV-vis surface plasmon resonance (SPR) intensity at 320 nm of the Cu2O NFs and the concentration of copper in cotton was determined. The laundering durability of the Cu2O NF-cotton fabric was investigated, and the superior nanoparticle-leach resistance was observed, with the fabrics releasing only 19% of copper after 50 home laundering cycles. The internally immobilized Cu2O NFs within the cotton fiber exhibited continuing antibacterial activity (≥99.995%) against K. pneumoniae, E. coli and S. aureus), complete antifungal activity (100%) against A. niger and antiviral activity (≥90%) against Human coronavirus, strain 229E, even after 50 laundering cycles.

Thermosensitive textiles made from silver nanoparticle-filled brown cotton fibers.

Filling fibers with nanomaterials can create new functions or modify the existing properties. However, as nanocomposite formation for natural cellulosic fibers has been challenging, little information is available on how the embedded nanomaterials alter the properties of cellulosic fibers. Here we filled brown cotton fibers with silver nanoparticles (Ag NPs) to examine their thermosensitive properties. Using naturally present tannins in brown cotton fibers as a reducing agent, Ag NP-filled brown cotton fibers (nanoparticle diameter of about 28 nm, weight fraction of 12 500 mg kg-1) were produced through a one-step process without using any external agents. The in situ formation of Ag NPs was uniform across the nonwoven cotton fabric and was concentrated in the lumen of the fibers. The insertion of Ag NPs into the fibers shifted the thermal decomposition of cellulose to lower temperatures with increased activation energy and promoted heat release during combustion. Ag NPs lowered the thermal effusivity of the fabric, causing the fabric to feel warmer than the control brown cotton. Ag NP-filled brown cotton was more effectively heated to higher temperatures than control brown cotton under the same heating treatments.

Application of Lignin-Containing Cellulose Nanofibers and Cottonseed Protein Isolate for Improved Performance of Paper.

There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry strength of filter paper. The application of 10% protein solution with 2% LCNFs as an additive improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Improvements in tensile modulus and tensile strength were greatest for samples containing larger amounts of lignin and a greater degree of polymerization than for those with less lignin from the same biomass sources.

Silver Nanoparticle-Intercalated Cotton Fiber for Catalytic Degradation of Aqueous Organic Dyes for Water Pollution Mitigation.

Azo dyes are commonly used in textile color processing for their wide array of vibrant colors. However, in recent years these dyes have become of concern in wastewater management given their toxicity to humans and the environment. In the present work, researchers remediated water contaminated with azo dyes using silver nanoparticles (Ag NPs) intercalated within cotton fabric as a catalyst, for their enhanced durability and reusability, in a reductive degradation method. Three azo dyes­methyl orange (MO), Congo red (CR), and Chicago Sky Blue 6B (CSBB)­were investigated. The azo degradation was monitored by UV/vis spectroscopy, degradation capacity, and turnover frequency (TOF). The Ag NP−cotton catalyst exhibited excellent degradation capacity for the dyes, i.e., MO (96.4% in 30 min), CR (96.5% in 18.5 min), and CSBB (99.8% in 21 min), with TOFs of 0.046 min−1, 0.082 min−1, and 0.056 min−1, respectively, using a 400 mg loading of catalyst for 100 mL of 25 mg L−1 dye. To keep their high reusability while maintaining high catalytic efficiency of >95% degradation after 10 cycles, Ag NPs immobilized within cotton fabric have promising potential as eco-friendly bio-embedded catalysts.

Structure/Function Analysis of Truncated Amino-Terminal ACE2 Peptide Analogs That Bind to SARS-CoV-2 Spike Glycoprotein.

The global burden of the SARS-CoV-2 pandemic is thought to result from a high viral transmission rate. Here, we consider mechanisms that influence host cell-virus binding between the SARS-CoV-2 spike glycoprotein (SPG) and the human angiotensin-converting enzyme 2 (ACE2) with a series of peptides designed to mimic key ACE2 hot spots through adopting a helical conformation analogous to the N-terminal α1 helix of ACE2, the region experimentally shown to bind to the SARS-CoV-2 receptor-binding domain (RBD). The approach examines putative structure/function relations by assessing SPG binding affinity with surface plasmon resonance (SPR). A cyclic peptide (c[KFNHEAEDLFEKLM]) was characterized in an α-helical conformation with micromolar affinity (KD = 500 µM) to the SPG. Thus, stabilizing the helical structure of the 14-mer through cyclization improves binding to SPG by an order of magnitude. In addition, end-group peptide analog modifications and residue substitutions mediate SPG binding, with net charge playing an apparent role. Therefore, we surveyed reported viral variants, and a correlation of increased positive charge with increased virulence lends support to the hypothesis that charge is relevant to enhanced viral fusion. Overall, the structure/function relationship informs the importance of conformation and charge for virus-binding analog design.

Ascorbic Acid as an Adjuvant to Unbleached Cotton Promotes Antimicrobial Activity in Spunlace Nonwovens.

The development of affordable, effective, and environmentally friendly barrier fabrics is a current goal in antimicrobial textile development. The discovery of new routes to achieve non-toxic naturally occurring molecules with antimicrobial activity is of interest in the development of materials that promote wound healing, improve hygiene, and offer protection against nosocomial infection. Highly cleaned and sterile unbleached cotton has constituents that produce hydrogen peroxide at levels commensurate with those that favor cell signaling in wound healing. Here, we show the antimicrobial and antiviral properties of spunlaced griege cotton-containing nonwovens treated with ascorbic acid formulations. The mechanism of action occurs through the promotion of enhanced hydrogen peroxide activity. The levels of hydrogen peroxide activity afford antimicrobial activity against Gram-negative and Gram-positive bacteria and antiviral activity against MS2 bacteriophages. Spun-bond nonwoven unbleached cotton was treated with ascorbic acid using traditional pad-dry-cure methods. An assessment of antibacterial and antiviral activity against Staphylococcus aureus, Klebsiella pneumoniae, and MS2 bacteriophages with the AATCC 100 test method showed a 99.99% inhibitory activity. An approach to the covalent attachment of ascorbic to cellulose through citric acid crosslinking chemistry is also discussed. Thus, a simple, low-cost approach to antimicrobial and antiviral cotton-based nonwovens applicable to dressings, nosocomial barrier fabrics, and face masks can be adopted by combining ascorbic acid with spunlace greige cotton nonwoven fabrics.

Detection of Human Neutrophil Elastase by Fluorescent Peptide Sensors Conjugated to TEMPO-Oxidized Nanofibrillated Cellulose.

Peptide-cellulose conjugates designed for use as optical protease sensors have gained interest for point-of-care (POC) detection. Elevated serine protease levels are often found in patients with chronic illnesses, necessitating optimal biosensor design for POC assessment. Nanocellulose provides a platform for protease sensors as a transducer surface, and the employment of nanocellulose in this capacity combines its biocompatibility and high specific surface area properties to confer sensitive detection of dilute biomarkers. However, a basic understanding of the spatiotemporal relationships of the transducer surface and sensor disposition is needed to improve protease sensor design and development. Here, we examine a tripeptide, fluorogenic elastase biosensor attached to TEMPO-oxidized nanofibrillated cellulose via a polyethylene glycol linker. The synthetic conjugate was found to be active in the presence of human neutrophil elastase at levels comparable to other cellulose-based biosensors. Computational models examined the relationship of the sensor molecule to the transducer surface. The results illustrate differences in two crystallite transducer surfaces ((110) vs. (1-10)) and reveal preferred orientations of the sensor. Finally, a determination of the relative (110) vs. (1-10) orientations of crystals extracted from cotton demonstrates a preference for the (1-10) conformer. This model study potentiates the HNE sensor results for enhanced sensor activity design.

Effect of Nanocellulose on the Properties of Cottonseed Protein Isolate as a Paper Strength Agent.

Currently, there is an increasing interest in the use of biopolymers in industrial applications to replace petroleum-based additives, since they are abundantly available, renewable and sustainable. Cottonseed protein is a biopolymer that, when used as a modifier, has shown improved performance for wood adhesives and paper products. Thus, it would be useful to explore the feasibility of using cellulose nanomaterials to further improve the performance of cottonseed protein as a paper strength agent. This research characterized the performance of cottonseed protein isolate with/without cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) to increase the dry strength of filter paper. An application of 10% protein solution with CNCs (10:1) or CNFs (50:1) improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Further analysis using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) indicated that the cottonseed protein/nanocellulose composites interacted with the filter paper fibers, imparting an increased dry strength.

Antimicrobial and Hemostatic Activities of Cotton-Based Dressings Designed to Address Prolonged Field Care Applications.

INTRODUCTION: Developing affordable and effective hemostatic and antimicrobial wound dressings for prolonged field care (PFC) of open wounds is of interest to prevent infection, to prevent sepsis, and to conserve tissue viability. The need for an effective hemostatic dressing that is also antimicrobial is required of a hemostatic dressing that can be left in place for extended periods (days). This is particularly important in light of the existence of pathogens that have coagulopathy properties. Thus, dressings that provide effective hemostasis and reduction in the frequency of dressing changes, whereas exerting robust antimicrobial activity are of interest for PFC. Highly cleaned and sterile unbleached cotton has constituents not found in bleached cotton that are beneficial to the hemostatic and inflammatory stages of wound healing. Here, we demonstrate two approaches to cotton-based antimicrobial dressings that utilize the unique components of the cotton fiber with simple modification to confer a high degree of hemostatic and antimicrobial efficacy. METHODS: Spun bond nonwoven unbleached cotton was treated using traditional pad dry cure methods to add ascorbic acid, zeolite (NaY) with pectin, calcium chloride, and sodium carbonate/calcium chloride. Similarly, nanosilver-embedded cotton fiber was blended with pristine cotton fibers at various weight ratios to produce hydroentangled nonwoven fabrics. The resulting treated fabrics were assessed for hemostasis using thromboelastographic clotting assays and antimicrobial activity utilizing American Association of Textile Chemists and Colorists 100. RESULTS: Zeolite-containing dressings possessed significant hemostatic activity, whereas ascorbic acid- and silver-containing dressings reduced Gram-positive and Gram-negative organism numbers by several logs. CONCLUSION: Based on this study, a multilayered hemostatic dressing with antimicrobial properties is envisioned. This dressing would be safe, would be economical, and have a stable shelf-life that would be conducive for using PFC.

Development of a Nonwoven Hemostatic Dressing Based on Unbleached Cotton: A De Novo Design Approach.

Minimally processed greige (unbleached) cotton fibers demonstrate enhanced clotting relative to highly processed United States Pharmacopeia (USP) type 7 bleached cotton gauze. This effect is thought to be due to the material surface polarity. We hypothesized that a textile could be constructed, conserving the hemostasis-accelerating properties of greige cotton, while maintaining structural integrity and improving absorbance. Spun bond nonwovens of varying surface polarity were designed and prepared based on ratios of greige cotton/bleached cotton/polypropylene fibers. A thromboelastographic analysis was performed on fibrous samples in citrated blood to evaluate the rate of fibrin and clot formation. Lee White clotting times were obtained to assess the material's clotting activity in platelet fresh blood. An electrokinetic analysis of samples was performed to analyze for material surface polarity. Hemostatic properties varied with composition ratios, fiber density, and fabric fenestration. The determinations of the surface polarity of cotton fabrics with electrokinetic analysis uncovered a range of surface polarities implicated in fabric-initiated clotting; a three-point design approach was employed with the combined use of thromboelastography, thrombin velocity index, Lee White clotting, and absorption capacity determinations applied to fabric structure versus function analysis. The resulting analysis demonstrates that greige cotton may be utilized, along with hydrophilic and hydrophobic fibers, to improve the initiation of fibrin formation and a decrease in clotting time in hemostatic dressings suitable to be commercially developed. Hydroentanglement is an efficient and effective process for imparting structural integrity to cotton-based textiles, while conserving hemostatic function.

Silver Nanoparticle-Infused Cotton Fiber: Durability and Aqueous Release of Silver in Laundry Water.

Although the application of silver nanoparticles to commercial antibacterial items is well-established, there have been increasing concerns that such particles might leach out, particularly into laundry water from textile products. A recently developed process wherein silver nanoparticles are synthesized in situ within the cotton fiber itself promises, however, to achieve the desired washing durability. In this study, the silver release behavior of the silver nanoparticle-infused cotton fabric during consecutive launderings in water and a detergent solution was analyzed. Silver nanoparticles (12 ± 3 nm in diameter) were uniformly produced throughout the entire volume of cotton fiber with a concentration of 3017 ± 56 mg/kg. A combination of colorimetric, spectroscopic, and elemental analyses showed (1) nonlinear silver release behavior, with a rapid release from externally formed nanoparticles during the initial washing and a plateau-like release from internally formed nanoparticles during extended washing, and (2) superior nanoparticle-leach resistance compared to those in commercial and laboratory-prepared textiles analyzed in the literature. The internal nanoparticles immobilized within cotton fiber exhibited persistent antibacterial activity after 50 home laundering cycles.

Method for identifying the triple transition (glass transition-dehydration-crystallization) of amorphous cellulose in cotton.

Although having a full picture of the heat-induced alterations in the fine structure of cellulosic materials is essential for designing their thermal processing, there have been no reliable methods to identify thermal transition temperatures. This study shows that colorimetric, thermogravimetric, and thermal kinetic parameters were sensitive to the thermochemical and thermo-structural changes in cotton fiber at low temperatures. Among these parameters, the activation energy for the thermal decomposition, evolving two local maxima against the preheating temperature, identified sequential thermal transformations in amorphous cellulose: 1) glass transition at 160-180 °C (Tg), 2) cellulose dehydration at 200-220 °C, and 3) crystallization at 240-260 °C. These results indicated that results of the mechanical tests or other methods discussed in the literature, which have produced inconsistent and higher Tg values (200-240 °C) for cellulosic materials, might have been misled by the dehydration of amorphous cellulose.

Cellulose hydrolysis using ionic liquids and inorganic acids under dilute conditions: morphological comparison of nanocellulose.

The preparation of cellulose nanocrystals (CNCs) from cellulose extracted from cotton gin motes (CGM) using an ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIm]Cl) under dilute conditions is reported. The concurrent process involves minimal swelling of cellulose with an ionic liquid and hydrolysis of the cellulose initiated by the addition of either phosphoric (H3PO4), hydrochloric (HCl), or sulfuric (H2SO4) acid. The obtained nanocrystals had similar physical properties (e.g. crystallinity) to the counterparts prepared under conventional conditions and exhibited superior thermal properties for sulfate CNCs. Additionally, the obtained CNCs had low surface functionalization, yet were colloidally stable for >90 days, which is a desirable trait for post-functionalization of CNCs. This process represents a general strategy utilizing dilute ionic liquids in the preparation of nanocellulose under mildly acidic conditions.

Thermal properties and surface chemistry of cotton varieties mineralized with calcium carbonate polymorphs by cyclic dipping.

In this study, hydroentangled cotton nonwovens were identified as effective hosts for mineralization of calcium carbonate (CaCO3) polymorphs to modify and improve their properties. All cotton varieties studied, including raw white cotton, scoured white cotton, and raw brown cotton, readily crystallized CaCO3 via a simple cyclic dipping process. A combination of analyses agreed that the surface chemistry of cotton fibers influenced the formation of different CaCO3 polymorphs. Scoured white cotton that consisted of almost pure cellulose predominantly produced the most stable calcite, whereas raw white and raw brown cottons that contain proteins facilitated the production of partial metastable vaterite. The morphology of calcite was better defined on the scoured cotton. The mineralization altered the hydrophobic surface of raw cottons to be hydrophilic, i.e., two-fold increase in moisture regain and decrease in water contact angle from 130 to 0 degrees. The mineralized cottons also exhibited improved thermal resistance, i.e., slower thermal decomposition with decreased activation energies and reduction in heat release capacity by up to 40%.

Alkali Hydrolysis of Sulfated Cellulose Nanocrystals: Optimization of Reaction Conditions and Tailored Surface Charge.

Cellulose nanocrystals (CNCs) are a biorenewable resource, which may be chemically modified to impart specific properties. Modified CNCs have found use in imaging applications, as rheology modifiers, polymer reinforcements, barrier and/or optical films, and nanocomposites. Nanoparticle dimensions of CNCs are typically 5-10 nm in width, with lengths of <100-300 nm. However, the physical properties are dependent upon the number and nature of the surface charge groups imparted during preparation. In the case of CNCs produced from sulfuric acid hydrolysis, the sulfated surface groups may be partially removed prior to further functionalization. This gives more available hydroxyls yet renders the CNCs less colloidally stable. Furthermore, conditions vary significantly and there is no consensus about the optimal conditions for partial removal of sulfate functionality or conditions developed to give specific surface charge. In the following, alkali hydrolysis of sulfate half-esters was quantified by conductometric titration of the strong acid groups, and using a design of experiments (DOE), optimal conditions were determined to produce CNCs with tailored surface charge.