Preparation of Colored Microcapsule Phase Change Materials with Colored SiO2 Shell for Thermal Energy Storage and Their Application in Latex Paint Coating

This article reports the design and manufacture of colored microcapsules with specific functions and their application in architectural interior wall coating. Utilizing reactive dyes grafted SiO2 shell to encapsulate paraffin through interfacial polymerization and chemical grafting methods, this experiment successfully synthesized paraffin@SiO2 colored microcapsules. The observations of surface morphology demonstrated that the colored microcapsules had a regular spherical morphology and a well-defined core-shell structure. The analysis of XRD and FT-IR confirmed the presence of amorphous SiO2 shell and the grafting reactive dyes, and the paraffin possessed high crystallinity. Compared with pristine paraffin, the thermal conductivity of paraffin@SiO2 colored microcapsules was significantly enhanced. The results of DSC revealed that the paraffin@SiO2 colored microcapsules performed high encapsulation efficiency and desirable latent heat storage capability. Besides, the examinations of UV-vis and TGA showed that the paraffin@SiO2 colored microcapsules exhibited good thermal reliability, thermal stability, and UV protection property. The analysis of infrared imaging indicated that the prepared latex paint exhibited remarkable temperature-regulated property. Compared with normal interior wall coatings, the temperature was reduced by about 2.5 °C. With such incomparable features, the paraffin@SiO2 colored microcapsules not only appeared well in their solar thermal energy storage and temperature-regulated property, but also make the colored latex paint coating have superb colored fixing capabilities.

In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

An Investigation Into The Fouling Phenomena Of Polycarbonate Membranes Used In The Treatment Of Latex Paint Wastewater

The treatment of latex paint wastewater with ultrafiltration allows for the reuse of the filtrate as process water or for cleaning purposes, as well as the potential for reclamation of the valuable paint solids. In this study, the utilization of polycarbonate membranes for the ultrafiltration of dilute latex dispersions was evaluated. Hydrophilic, flat sheet ultrafiltration membranes with a mean pore size of 0.1 μm were used. All filtration experiments were conducted under constant pressure operation, in a circular, centre-fed, cross-flow filtration cell. The effect of feed flow rate was investigated, and the steady-state permeate flux achieved showed an increase of 294% between 1.0 and 3.0 L/min. Increasing the operating pressure also resulted in an increased permeate flux, with a 320% increase from 1.5 to 5.5 psi. Also considered was the effect of the feed solid concentration on the permeate flux. When compared to the clean water flux (0% solids) of 5.5×10- Surfactant-enhanced ultrafiltration was also studied, with concentrations ranging from 25% to 200% of the literature values of the surfactant's critical micelle concentration (CMC) in pure water. The addition of an anionic surfactant, sodium dodecyl sulphate (SDS), reduced the effectiveness of the filtration. However, the addition of a cationic surfactant, cetyl trimethylammonium bromide (CTAB), increased the permeate flux of the latex dispersion up to 130% when twice its CMC was used, with evidence of a reduction in the effect of fouling of the membranes. This may be due to repelling interactions between the surface of the membrane and the surface of the formed micelles, as well as a reduced cake resistance due to the larger particle size of the constituents forming a less dense cake layer.

An Investigation Into The Fouling Phenomena Of Polycarbonate Membranes Used In The Treatment Of Latex Paint Wastewater

The treatment of latex paint wastewater with ultrafiltration allows for the reuse of the filtrate as process water or for cleaning purposes, as well as the potential for reclamation of the valuable paint solids. In this study, the utilization of polycarbonate membranes for the ultrafiltration of dilute latex dispersions was evaluated. Hydrophilic, flat sheet ultrafiltration membranes with a mean pore size of 0.1 μm were used. All filtration experiments were conducted under constant pressure operation, in a circular, centre-fed, cross-flow filtration cell. The effect of feed flow rate was investigated, and the steady-state permeate flux achieved showed an increase of 294% between 1.0 and 3.0 L/min. Increasing the operating pressure also resulted in an increased permeate flux, with a 320% increase from 1.5 to 5.5 psi. Also considered was the effect of the feed solid concentration on the permeate flux. When compared to the clean water flux (0% solids) of 5.5×10- Surfactant-enhanced ultrafiltration was also studied, with concentrations ranging from 25% to 200% of the literature values of the surfactant's critical micelle concentration (CMC) in pure water. The addition of an anionic surfactant, sodium dodecyl sulphate (SDS), reduced the effectiveness of the filtration. However, the addition of a cationic surfactant, cetyl trimethylammonium bromide (CTAB), increased the permeate flux of the latex dispersion up to 130% when twice its CMC was used, with evidence of a reduction in the effect of fouling of the membranes. This may be due to repelling interactions between the surface of the membrane and the surface of the formed micelles, as well as a reduced cake resistance due to the larger particle size of the constituents forming a less dense cake layer.

Improving the Accuracy of a Hygrothermal Model for Wood-Frame Walls: A Cold-Climate Study

A one-dimensional transient hygrothermal model was used to simulate eight different wood-frame wall assemblies. Simulations were compared with measured results from a two-year field study exploring the effects of exterior insulation on wall moisture performance in a cold-climate. The field study documented the moisture content, temperature, and relative humidity measurements in wall assemblies using oriented strand board (OSB) sheathing. Simulations were performed using generic design input values as well as input values based on measurements or sensitivity analysis. Laboratory material property measurements informed the choice of material property values in the improved model for OSB, asphalt-coated kraft paper, and interior latex paint. Simulations using improved input values typically agreed with field measurements within measurement error. The most significant model improvements were all related to vapor permeance. The vinyl siding used an effective permeance much lower than typically recommended. However, both the extruded polystyrene insulation and the asphalt-coated kraft paper facing on the cavity fiberglass insulation had higher permeance than literature values.

Efficacy of expanded polystyrene as fine aggregate in cement mortars modified with latex paint as an alternative to polymer admixture

In this present study, the effectiveness of expanded polystyrene (EPS) waste used as 20, 40 and 60% fine sand replacement in development of lightweight cement composite was evaluated. The cement mortar was strengthened by 10% low cost latex paint emulsion as an alternative to the more expensive polymer admixtures. Six different mix designs were produced and tested for compressive and split tensile strength according to BS EN standards. Scanning electron microscope (SEM) analysis was also conducted to analysis the micrograph of the samples. It was observed that as the EPS content, latex paint polymer admixture and curing days were increased, marginal increment in compressive strength was obtained. However, EPS fines were most effective in improving the split strength while latex paint admixture had comparatively less part to play in the strength development. The micrograph images showed that the EPS fines were uniformly distributed within the microstructure and the latex paint developed polymer films. These mechanisms coupled with the cement hydrate products were responsible for the enhanced strength observed in the samples.