Microplastic extraction protocols can impact the polymer structure

AbstractAlthough microplastics are ubiquitous in today’s natural environments, our understanding of the materials, quantities, and particle sizes involved remains limited. The recovery of microplastics from different types of environmental matrices requires standardized matrix digestion protocols that allow inter-laboratory comparisons and that have no effect on the polymers themselves. A number of commonly used digestion methods rely on oxidation with concentrated hydrogen peroxide solutions to remove organic matter from the matrix. However, this can alter the nature of polymers through hydrolysis and often does not lead to a complete matrix removal. We have therefore investigated the use of two altered matrix digestion protocols, an acidic (Fenton) protocol and a new alkaline (Basic Piranha) protocol, focusing mainly on the effect on biodegradable polymers (polylactide, polybutylene adipate terephthalate, polybutylene succinate) and polymers with known degradation pathways via hydrolysis (thermoplastic polyurethanes, polyamide). Comparing the initial surface textures, chemical compositions, and particle size distributions with those obtained after digestion revealed that the Fenton protocol left most of the polymers unchanged. The ferrous residue that remains following Fenton digestion had no effect on either the polymer composition or the particle size distribution, but could disturb further analytics (e.g. Raman microscopy due to auto-fluorescence). While increasing the chance of complete matrix removal, the more powerful Basic Piranha protocol is also more likely to affect the polymer properties: Polylactide polymers in particular showed signs of degradation under alkaline digestion (reduced polylactide content, holes in the polymer matrix), indicating the unsuitability of the Basic Piranha protocol in this specific case. Polyamide, however, remained stable during the Basic Piranha treatment, and the surface chemistry, the particle size as well as the molar mass distribution of the investigated thermoplastic polyurethanes were also not affected. Hence, this protocol offers a powerful alternative for microplastic analysis with focus on particle size in more complex environmental matrices (e.g. removal of cellulose in soil), while avoiding ferrous Fenton residue. Unexpectedly, also tire rubber, a frequent target analyte in microplastic monitoring, was found to be susceptible to artefact structures by both oxidation protocols. In summary, controls for the specific combination of polymer and sample preparation protocol are highly recommended to select the most fitting protocol. Here selected suitable combinations are reported.

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Amorphous Calcium Phosphate Based Polymeric Composites: Effects of Polymer Composition and Filler's Particle Size on Composite Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.284-286.737 ◽

2005 ◽

Vol 284-286 ◽

pp. 737-740 ◽

Cited By ~ 4

Author(s):

Drago Skrtic ◽

S.Y. Lee ◽

Joseph M. Antonucci ◽

D.W. Liu

Keyword(s):

Particle Size ◽

Calcium Phosphate ◽

Physicochemical Properties ◽

Amorphous Calcium Phosphate ◽

Fine Tuning ◽

Polymer Composition ◽

Ion Release ◽

The Matrix ◽

Carboxylic Groups ◽

Composite Properties

This study explores how a) the resin grafting potential for amorphous calcium phosphate (ACP) and b) particle size of ACP affects physicochemical properties of composites. Copolymers and composites were evaluated for biaxial flexure strength (BFS), degree of vinyl conversion (DC), mineral ion release and water sorption (WS). Milled ACP composites were superior to unmilled ACP composites and exhibited 62 % and 77 % higher BFS values (dry and wet state, respectively). The average DC of copolymers 24 h after curing was 80 %. DC of composites decreased 10.3 % for unmilled Zr-ACP and 4.6 % for milled Zr-ACP when compared to the corresponding copolymers. The WS increased as follows: copolymers < milled Zr-ACP composites < unmilled Zr-ACP composites. The levels of Ca and PO4 released from both types of composites increased with the increasing EBPADMA/TEGDMA ratio in the matrix. They were significantly above the minimum necessary for the redeposition of HAP to occur. No significant consumption of released calcium by the carboxylic groups of methacryloxyethyl phtahalate (MEP) occurred at a mass fraction of 2.6 % of MEP in the resin. Improvements in ACP composite’s physicochemical properties are achieved by fine tuning of the resin and improved ACP’s dispersion within the polymer matrix after ball-milling.

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The Influence of Filler Size and Crosslinking Degree of Polymers on Mullins Effect in Filled NR/BR Composites

Polymers ◽

10.3390/polym13142284 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2284

Author(s):

Miaomiao Qian ◽

Bo Zou ◽

Zhixiao Chen ◽

Weimin Huang ◽

Xiaofeng Wang ◽

...

Keyword(s):

Particle Size ◽

Strain Energy ◽

Mathematical Expression ◽

Rubber Matrix ◽

Mullins Effect ◽

Butadiene Rubber ◽

Crosslinking Degree ◽

Test Range ◽

Two Factors ◽

The Matrix

Two factors, the crosslinking degree of the matrix (ν) and the size of the filler (Sz), have significant impact on the Mullins effect of filled elastomers. Herein, the result. of the two factors on Mullins effect is systematically investigated by adjusting the crosslinking degree of the matrix via adding maleic anhydride into a rubber matrix and controlling the particle size of the filler via ball milling. The dissipation ratios (the ratio of energy dissipation to input strain energy) of different filled natural rubber/butadiene rubber (NR/BR) elastomer composites are evaluated as a function of the maximum strain in cyclic loading (εm). The dissipation ratios show a linear relationship with the increase of εm within the test range, and they depend on the composite composition (ν and Sz). With the increase of ν, the dissipation ratios decrease with similar slope, and this is compared with the dissipation ratios increase which more steeply with the increase in Sz. This is further confirmed through a simulation that composites with larger particle size show a higher strain energy density when the strain level increases from 25% to 35%. The characteristic dependence of the dissipation ratios on ν and Sz is expected to reflect the Mullins effect with mathematical expression to improve engineering performance or prevent failure of rubber products.

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Phase evolution, characterisation, and performance of cement prepared in an oxy-fuel atmosphere

Faraday Discussions ◽

10.1039/c6fd00032k ◽

2016 ◽

Vol 192 ◽

pp. 113-124 ◽

Cited By ~ 9

Author(s):

Liya Zheng ◽

Thomas P. Hills ◽

Paul Fennell

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Particle Size Distribution ◽

Size Distribution ◽

Carbon Capture ◽

Raw Materials ◽

Carbon Capture And Storage ◽

Phase Evolution ◽

Chemical Compositions ◽

Phase And Elemental Compositions

Cement manufacture is one of the major contributors (7–10%) to global anthropogenic CO2 emissions. Carbon capture and storage (CCS) has been identified as a vital technology for decarbonising the sector. Oxy-fuel combustion, involving burning fuel in a mixture of recycled CO2 and pure O2 instead of air, makes CO2 capture much easier. Since it combines a theoretically lower energy penalty with an increase in production, it is attractive as a CCS technology in cement plants. However, it is necessary to demonstrate that changes in the clinkering atmosphere do not reduce the quality of the clinker produced. Clinkers were successfully produced in an oxy-fuel atmosphere using only pure oxides as raw materials as well as a mixture of oxides and clay. Then, CEM I cements were prepared by the addition of 5 wt% gypsum to the clinkers. Quantitative XRD and XRF were used to obtain the phase and elemental compositions of the clinkers. The particle size distribution and compressive strength of the cements at 3, 7, 14, and 28 days' ages were tested, and the effect of the particle size distribution on the compressive strength was investigated. Additionally, the compressive strength of the cements produced in oxy-fuel atmospheres was compared with those of the cement produced in air and commercially available CEMEX CEM I. The results show that good-quality cement can be successfully produced in an oxy-fuel atmosphere and it has similar phase and chemical compositions to CEM I. Additionally, it has a comparable compressive strength to the cement produced in air and to commercially available CEMEX CEM I.

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Synthesis of nontronite and other Fe-rich smectites: a critical review

Clay Minerals ◽

10.1180/claymin.2017.052.4.05 ◽

2017 ◽

Vol 52 (4) ◽

pp. 469-483 ◽

Cited By ~ 7

Author(s):

S. Petit ◽

F. Baron ◽

A. Decarreau

Keyword(s):

Clay Minerals ◽

Critical Review ◽

Present Review ◽

Chemical Compositions ◽

Natural Environments ◽

The Past

AbstractThe synthesis of clay minerals has been studied for decades in an attempt to better understand their formation in natural environments and more recently to obtain clay minerals with controlled compositions and properties. Even though nontronite has been synthesized successfully since 1935, the process is not a straightforward and has been poorly documented. In the present review concerning the synthesis of nontronite and other Fe-rich smectites, the experiments attempted in the past are discussed critically in light of the most recent data. Most notably, the application of relationships established recently, thanks to synthetic smectitic series, have allowed us to refine the chemical compositions of some nontronites synthesized previously.

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Rapid measurement of particle hygroscopicity and CCN activity using broad scanning supersaturation (BS2)-CCNC: calibration and intercomparison

10.5194/egusphere-egu21-8067 ◽

2021 ◽

Author(s):

Najin Kim ◽

Yafang Cheng ◽

Nan Ma ◽

Mira Pöhlker ◽

Thomas Klimach ◽

...

Keyword(s):

Particle Size ◽

Time Resolution ◽

Calibration Curve ◽

Aerosol Particles ◽

High Time ◽

Activity Measurement ◽

High Time Resolution ◽

Chemical Compositions ◽

Monotonic Relation ◽

Ccn Activity

For understanding and assessing aerosol-cloud interactions and their impact on climate, reliable measurement data of aerosol particle hygroscopicity and cloud condensation nuclei (CCN) activity are required. Furthermore, aerosol liquid water, mainly controlled by hygroscopicity, affects heterogeneous and multiphase reactions of aerosol particles. The CCN activity of aerosol particles can be determined by scanning particle size and supersaturation (S) in the CCN measurement. Compared to the existing CCN activity measurement, a broad supersaturation scanning CCN (BS2-CCN) system, in which particles are exposed to a range of S simultaneously, can measure particle hygroscopicity and CCN activity with a high-time resolution. Based on a monotonic relation between the activation supersaturation of aerosol particles (Saerosol) &#160;and the activation fraction (Fact) of the BS2-CCN measurement, we can derive &#954;, a single hygroscopicity parameter, directly.Here, we describe how the BS2-CCN system can be effectively calibrated and which factors can affect the calibration curve (Fact - Saerosol). For calibration, size-resolved CCN measurements with ammonium sulfate (AS) and sodium chloride particles are performed under the three different thermal gradient (dT) conditions (dT=6, 8, and 10). First, the shape of the calibration curve is primarily influenced by Smax, maximum S in the activation tube. We need to determine appropriate Smax depending on particle size and &#954; to be investigated. To minimize the effect of double/multiple charged particles, small&#160; Dg and &#963;g&#160; in number size distribution are recommended when generating the calibration aerosols. Sheath-to-aerosol-flow ratio (SAR) is the third factor to be considered. BS2-CCNC system uses a low SAR with a wider inlet compared to the typical CCN measurement, which can make a monotonic relation between Fact and Saerosol. Lastly, Fact is affected by particle number concentration and has a decreasing rate of 0.02/100 cm-3 (within NCN ~ 300 cm-3 for AS) due to the water consumption in the chamber. For evaluating the BS2-CCN system, inter-comparison experiments between typical DMA-CCN and BS2-CCN measurement were performed with the laboratory-generated aerosol mixture and ambient aerosols. Statistically good agreements of &#954; values between DMA-CCN and BS2-CCN measurements for both inter-comparison experiments imply that the BS2-CCN system can measure particle hygroscopicity and CCN activity well compared to the existing measurement. We expect that this new system can be applied to aircraft and ship measurements that require a high-time resolution as well as ground measurement for a broad range of hygroscopicity distribution. Because hygroscopicity is closely related to the fraction of organics/inorganics in aerosol particles, our method can also serve as a complementary approach for fast detection/estimation of aerosol chemical compositions.&#160;

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Principle of Strength Reinforcement in Filled Rubbers

Rubber Chemistry and Technology ◽

10.5254/1.3539147 ◽

1967 ◽

Vol 40 (5) ◽

pp. 1337-1363 ◽

Cited By ~ 55

Author(s):

A. E. Oberth

Keyword(s):

Particle Size ◽

Crosslink Density ◽

High Modulus ◽

Stress Concentrations ◽

Volume Increase ◽

The Matrix ◽

Filled Rubbers ◽

Filler Particles ◽

Tear Properties ◽

Properties Of Composites

Abstract Effects of filler on mechanical properties of composites result from stress concentrations developed in the matrix and filler particles. Stress concentrations in filler particles relieve stress in the matrix which, under a given load, deforms less than it would in absence of filler. This accounts for high modulus as well as strength reinforcement in filled materials. Stress concentration in the matrix, decreasing with increasing content of filler, is responsible for internal tearing of composites. Magnitude of this internal tearing, which can be measured by volume increase of a specimen under strain, depends on many factors such as: shape of filler, orientation of filler particles, particle size, particle size distribution, nature of boundary layer between filler and matrix, crosslink density and tear properties of the matrix, as well as environmental pressure in the test. High dilatation results in low tensile strength of the composite and conversely if dilatation is suppressed maximum strength reinforcement is obtained.

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Determination of Particle Size in Powders by Scatter Correction in Diffuse Near-Infrared Reflectance

Applied Spectroscopy ◽

10.1366/0003702884429058 ◽

1988 ◽

Vol 42 (5) ◽

pp. 722-728 ◽

Cited By ~ 57

Author(s):

J. L. Ilari ◽

H. Martens ◽

T. Isaksson

Keyword(s):

Particle Size ◽

Near Infrared ◽

Scatter Correction ◽

Large Degree ◽

Chemical Compositions ◽

Infrared Reflectance ◽

Near Infrared Reflectance ◽

Analytical Technique ◽

Scattering Effects ◽

Reflectance Data

Diffuse near-infrared reflectance spectroscopy has traditionally been an analytical technique for determining chemical compositions in a sample. We will, in this paper, focus on light scattering effects and their ability to determine the mean particle sizes of powders. The reflectance data of NaCl, broken glass, and sorbitol powders are linearized and submitted to the Multiplicative Scatter Correction (MSC), and the ensuing parameters are used in subsequent multivariate calibrations. The results indicate that particle size can, to a large degree, be determined from NIR reflectance data for a given type of powder. Up to 99% of the partical size variance was explained by the regression.

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Thermal History of Matrix Forsterite Grains from Murchison Based on High-resolution Tomography

The Astrophysical Journal ◽

10.3847/1538-4357/ac26bc ◽

2021 ◽

Vol 922 (2) ◽

pp. 256

Author(s):

Giulia Perotti ◽

Henning O. Sørensen ◽

Henning Haack ◽

Anja C. Andersen ◽

Dario Ferreira Sanchez ◽

...

Keyword(s):

High Resolution ◽

Electron Density ◽

Chemical Compositions ◽

X Ray Diffraction ◽

X Ray ◽

Density Maps ◽

Thermally Processed ◽

The Matrix ◽

History Of ◽

Chondrule Formation

Abstract Protoplanetary disks are dust- and gas-rich structures surrounding protostars. Depending on the distance from the protostar, this dust is thermally processed to different degrees and accreted to form bodies of varying chemical compositions. The primordial accretion processes occurring in the early protoplanetary disk such as chondrule formation and metal segregation are not well understood. One way to constrain them is to study the morphology and composition of forsteritic grains from the matrix of carbonaceous chondrites. Here, we present high-resolution ptychographic X-ray nanotomography and multimodal chemical microtomography (X-ray diffraction and X-ray fluorescence) to reveal the early history of forsteritic grains extracted from the matrix of the Murchison CM2.5 chondrite. The 3D electron density maps revealed, at unprecedented resolution (64 nm), spherical inclusions containing Fe–Ni, very little silica-rich glass and void caps (i.e., volumes where the electron density is consistent with conditions close to vacuum) trapped in forsterite. The presence of the voids along with the overall composition, petrological textures, and shrinkage calculations is consistent with the grains experiencing one or more heating events with peak temperatures close to the melting point of forsterite (∼2100 K), and subsequently cooled and contracted, in agreement with chondrule-forming conditions.

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Numerical Simulation on Nanoparticles Integrated Laser Shock Peening of Aluminum Alloy

ASME 2009 International Manufacturing Science and Engineering Conference, Volume 1 ◽

10.1115/msec2009-84088 ◽

2009 ◽

Author(s):

Chang Ye ◽

Gary J. Cheng

Keyword(s):

Numerical Simulation ◽

Particle Size ◽

Laser Shock Peening ◽

Particle Orientation ◽

Stress Wave Propagation ◽

Stress And Strain ◽

Laser Shock ◽

The Matrix ◽

Final Stress ◽

Shock Peening

In this paper, numerical simulation of nanoparticle integrated laser shock peening of aluminum alloys was carried out. A “tied constraint” was used to connect the matrix and nanoparticle assembly in ABAQUS package. Different particle size and particle volumes fraction (PVF) were studied. It was found that there is significant stress concentration around the nanoparticles. The existence of nanoparticle will influence the stress wave propagation and thus the final stress and strain state of the material after LSP. In addition, particle size, PVF and particle orientation all influence the strain rate, static residual stress, static plastic strain and energy absorption during the LSP process.

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Molecular and morphometric characterisation of Xiphinema globosum Sturhan, 1978 (Nematoda: Longidoridae) from Spain

Nematology ◽

10.1163/138855410x500046 ◽

2011 ◽

Vol 13 (1) ◽

pp. 17-28 ◽

Cited By ~ 3

Author(s):

Blanca Landa ◽

Carolina Cantalapiedra-Navarrete ◽

Juan Palomares-Rius ◽

Pablo Castillo ◽

Carlos Gutiérrez-Gutiérrez

Keyword(s):

Phylogenetic Trees ◽

18S Rrna ◽

Matrix Representation ◽

Natural Environments ◽

28S Rrna ◽

Parsimony Method ◽

Rdna Genes ◽

Supertree Method ◽

The Matrix ◽

Relationship Of

AbstractDuring a recent nematode survey in natural environments of the Los Alcornocales Regional Park narrow valleys, viz., the renowned 'canutos' excavated in the mountains that maintain a humid microclimate, in southern Spain, an amphimictic population of Xiphinema globosum was identified. Morphological and morphometric studies on this population fit the original and previous descriptions and represent the first report from Spain and southern Europe. Molecular characterisation of X. globosum from Spain using D2-D3 expansion regions of 28S rRNA, 18S rRNA and ITS1-rRNA is provided and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships within X. globosum and other Xiphinema species. A supertree solution of the different phylogenetic trees obtained in this study and in other published studies using rDNA genes are presented using the matrix representation parsimony method (MRP) and the most similar supertree method (MSSA). The results revealed a closer phylogenetic relationship of X. globosum with X. diversicaudatum, X. bakeri and with some sequences of unidentified Xiphinema spp. deposited in GenBank.

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