Ageing and structural changes in PDMS rubber investigated by time domain NMR

Cunha, Giovanni Paro da; Filgueiras, Jefferson G.; Pinto, José M.; Munaro, Marilda; Azevêdo, Eduardo Ribeiro de; Akcelrud, Leni

doi:10.1016/j.polymdegradstab.2019.06.008

Cited by 12 publications

(10 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two large distribution peaks are located at lower residual dipolar coupling values (ω D /2π = 200 − 400 Hz), and two smallest peaks are located at larger residual dipolar coupling values (ω D /2π ≈ 1.075 − 1.3 kHz ). The peaks located at lower residual dipolar coupling values are in agreement with the results obtained by Nie et al [34] and with the distributions reported in [35,36,45]. After an aging in natural conditions, many of the NR1 polymer chains characterized by a small value of ω D /2π become more mobile and have a reduced residual dipolar coupling (see the left large peak).…”

Section: Proton Dq Laplace-like Spectra Of Aged Natural Rubbersupporting

confidence: 90%

Bimodal 1H Double Quantum Build-Up Curves by Fourier and Laplace-like Transforms on Aged Cross-Linked Natural Rubber

Moldovan

Fechete

2021

Polymers

View full text Add to dashboard Cite

The 1H DQ Fourier and Laplace-like spectra for a series of cross-linked natural rubber (NR) samples naturally aged during six years are presented and characterized. The DQ build-up curves of these samples present two peaks which cannot be described by classical functions. The DQ Fourier spectra can be obtained after a numeric procedure which introduces a correction time which depends less on the chosen approximation, spin-½ and isolated CH2 and CH3 functional groups. The DQ Fourier spectra are well described by the distributions of the residual dipolar coupling correlated with the distribution of the end-to-end vector of the polymer network, and with the second and fourth van Vleck moments. The deconvolution of DQ Fourier spectra with a sum of four Gaussian variates show that the center and the width of Gaussian functions increase linearly with the increase in the cross-link density. The Laplace-like spectra for the natural aged NR DQ build-up curves are presented. The centers of four Gaussian distributions obtained via both methods are consistent. The differences between the Fourier and Laplace-like spectra consist mainly of the spectral resolution in the favor of Laplace-like spectra. The last one was used to discuss the effect of natural aging for cross-linked NR.

show abstract

Section: Proton Dq Laplace-like Spectra Of Aged Natural Rubbersupporting

confidence: 90%

Bimodal 1H Double Quantum Build-Up Curves by Fourier and Laplace-like Transforms on Aged Cross-Linked Natural Rubber

Moldovan

Fechete

2021

Polymers

View full text Add to dashboard Cite

show abstract

“…The decrease is also responsible for the change in gel content and crosslinking density after centrifugation (Figure 2). Additionally, entanglements, which can function as crosslinking points, are a key component of natural network [39,[46][47][48][49]. On the basis of analyses mentioned above, we tentatively proposed a novel model for natural network structure of NR, as illustrated in Figure 4.…”

Section: Non-rubber Components and Structure Of Nr Cnr-1 And Cnr-2mentioning

confidence: 99%

Section: Non-rubber Components and Structure Of Nr Cnr-1 And Cnr-2mentioning

confidence: 99%

The Role of Non-Rubber Components on Molecular Network of Natural Rubber during Accelerated Storage

Zhang

Chen

et al. 2020

Polymers

View full text Add to dashboard Cite

Though the non-rubber components have long been recognized to be a vital factor affecting the network of natural rubber (NR), the authentic role of non-rubber components on the network during accelerated storage has not been fully illuminated. This work attempts to clarify the impact of non-rubber components on the network for NR during accelerated storage. A natural network model for NR was proposed based on the gel content, crosslinking density, and the non-rubber components distribution for NR before and after centrifugation. Furthermore, the effect of non-rubber components on the network was investigated during accelerated storage. The results show that terminal crosslinking induced by non-rubber components and entanglements are primary factors affecting the network formation during accelerated storage. By applying the tube model to analyze the stress-strain curves of NR, we found that the contribution of the entanglements to the network formation is larger than that of terminal crosslinking during accelerated storage. The work highlights the role of non-rubber components on the network during accelerated storage, which is essential for understanding the storage hardening mechanism of NR.

show abstract

“…The prime drawback is its hydrophobicity which leads to the creation of air bubbles in the channels and can absorb small hydrophobic molecules such as biomolecules and drugs in the solution in biological studies which ultimately bias the result for bio-experiments for which rising with ethanol before the experiment is suggested. The ageing of PDMS will alter its mechanical properties as well, and therefore it cannot be stored for a long time [ 26 ].…”

Section: Introduction and Overviewmentioning

confidence: 99%

Applications of Microfluidics and Organ-on-a-Chip in Cancer Research

et al. 2022

View full text Add to dashboard Cite

Taking the life of nearly 10 million people annually, cancer has become one of the major causes of mortality worldwide and a hot topic for researchers to find innovative approaches to demystify the disease and drug development. Having its root lying in microelectronics, microfluidics seems to hold great potential to explore our limited knowledge in the field of oncology. It offers numerous advantages such as a low sample volume, minimal cost, parallelization, and portability and has been advanced in the field of molecular biology and chemical synthesis. The platform has been proved to be valuable in cancer research, especially for diagnostics and prognosis purposes and has been successfully employed in recent years. Organ-on-a-chip, a biomimetic microfluidic platform, simulating the complexity of a human organ, has emerged as a breakthrough in cancer research as it provides a dynamic platform to simulate tumor growth and progression in a chip. This paper aims at giving an overview of microfluidics and organ-on-a-chip technology incorporating their historical development, physics of fluid flow and application in oncology. The current applications of microfluidics and organ-on-a-chip in the field of cancer research have been copiously discussed integrating the major application areas such as the isolation of CTCs, studying the cancer cell phenotype as well as metastasis, replicating TME in organ-on-a-chip and drug development. This technology’s significance and limitations are also addressed, giving readers a comprehensive picture of the ability of the microfluidic platform to advance the field of oncology.

show abstract

Ageing and structural changes in PDMS rubber investigated by time domain NMR

Cited by 12 publications

References 28 publications

Bimodal 1H Double Quantum Build-Up Curves by Fourier and Laplace-like Transforms on Aged Cross-Linked Natural Rubber

Bimodal 1H Double Quantum Build-Up Curves by Fourier and Laplace-like Transforms on Aged Cross-Linked Natural Rubber

The Role of Non-Rubber Components on Molecular Network of Natural Rubber during Accelerated Storage

Applications of Microfluidics and Organ-on-a-Chip in Cancer Research

Contact Info

Product

Resources

About