Effect of polymer-coated silica particles in a Portland cement matrix via in-situ infrared spectroscopy

Abstract

It is often of great importance in engineering to know precisely the properties of a material used with regard to its strength, its plasticity or its brittleness, its elasticity, and some other properties. For this purpose, material samples are tested in a tensile test by clamping the sample with a known starting cross-section in a tensile testing machine and loading it with a tensile force F. The force is then graphically displayed over the length change ΔL caused. This curve is called the force-extension diagram. In this study, a new measurement method enables for the first time, depending on the applied uniaxial stress, an insight at the atomic level into various energy dissipation processes at cement-based materials with the help of infrared spectroscopy. The samples are modified by adding SiO2 particles, which are coated by a polymer (PEG-MDI-DMPA) of different PEG molecular weights. Results show that elongating and breakage of [Formula: see text] and [Formula: see text] bonds play an essential role in the strain energy dissipation. Compared to the pure cement, the modified samples are affected more by elongating and breakage of [Formula: see text] as the admixture can effectively reduce the energy barrier of the hydrolytic reaction. The incorporating of particles into the cement matrix induces new mechanisms for energy dissipation by stretching of [Formula: see text] bending vibrations. Stretching vibration of the [Formula: see text] group indicates that part of the energy is dissipated by breakage of hydrogen bonding between the carboxyl group and PEG chains. Besides, a higher value of the ultimate fracture force following an increase in the molecular weight of PEG shows stronger bonding between particles and the cement matrix. As the chain-length of PEG is increased, less energy is absorbed through the other processes (especially at a higher level of strain). Thus, there is a balance between the whole deformation (toughness) and the strength of samples with the increase of the PEG molecular weight.

Preparation and Evaluation Mechanic Damping Properties of Fused Silica Powder@Polyurethane Urea/Cement Composites

“…Figure 4 shows FTIR spectra of the FSP and FSP@PUU in the 500–4000 cm −1 zone. In the FTIR spectra of FSP, the strong absorption bands at 3405 cm −1 , 1105 cm −1 and 2970–2869 cm −1 were due to the stretching vibrations of −OH groups, Si-O-Si groups and CH 2 and CH 3 groups, respectively [ 21 , 22 , 23 ]. In the FTIR spectra of FSP @PUU, new peaks of N-H (3349 cm −1 ) bonds, C = O (1678 cm −1 ) groups and C-O-C(1105 cm −1 ) groups were found, and the peak at 3405 cm −1 of -OH disappeared [ 24 ].…”

Increasing the Strain Resistance of Si/SiO2 Interfaces for Flexible Electronics

“…The device consists of a movable sample holder, moving toward a noise-like metal piece (see Figure A). The sample is placed inside a slot located in the sample holder. , The movable sample holder and the nose-like metal piece are connected through an open current circuit. When the sample encounters the nose-like metal piece for the first time, the circuit closes, which is defined as the zero position.…”

Strain Activation of Surface Chemistry on H-Terminated Si(111)

“…b and h are the width and thickness of the sample, respectively. The procedures to obtain the proposed equations were thoroughly outlined in our previous article . The applied values of deflection, strain, and force to get the strain in the range of 0.006–1% are presented in Table .…”