Fabrication of thermally expandable core–shell microcapsules using organic and inorganic stabilizers and their application

Jeoung, Sun Kyoung; Han, In Soo; Jung, Yung Jun; Hong, Sanghyun; Shim, Sang Eun; Hwang, Ye Jin; Lee, Pyoung‐Chan; Ha, Jin Uk

doi:10.1002/app.44247

Cited by 15 publications

(12 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermal expansion microspheres (TEMs) are polymer particles with core-shell structure, which are generally composed of thermoplastic polymer shell encapsulated with low boiling hydrocarbons [1]. Upon heating, the polymer shell softens, and the vapor pressure generated by the internal blowing agent causes microspheres to expand, the diameter of the expanded microspheres can be increased by 3-5 times [2]. After cooling, the microspheres still can maintain its expanded state.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of high temperature resistant thermal expansion microsopheres with P(acrylonitrile/methacrylic acid/N,N-dimethylacrylamide/n-butylacrylate) shell

Zhang

Zhou

Huang³

et al. 2019

SN Appl. Sci.

View full text Add to dashboard Cite

High temperature resistant microspheres were prepared via Pickering suspension polymerization. Acrylonitrile (AN), methacrylic acid (MAA) and N,N-dimethylacrylamide (DMAA) were used as monomers, and n-butylacrylate (BA) was used as modified monomer to improve the expansion properties of the microspheres. Morphology of the microspheres was characterized by scanning electron microscopy (SEM) and polarizing optical microscope (POM) respectively. The average diameter of the prepared microspheres was 51.9 μm, and the maximum expansion volume was 4 times of the original volume. The expansion performance and blowing agent content of the microspheres were characterized by thermal mechanical analysis (TMA) and thermogravimetric analysis (TGA) respectively. The onset expansion temperature of the microspheres was 159.5 °C, the maximum expansion temperature was 213.9 °C, and the encapsulation content of the blowing agent was 14.62%. Fourier transform infrared (FTIR) showed that the adjacent chains of AN and MAA form imide ring structure during the thermal expansion process of the microspheres.

show abstract

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of high temperature resistant thermal expansion microsopheres with P(acrylonitrile/methacrylic acid/N,N-dimethylacrylamide/n-butylacrylate) shell

Zhang

Zhou

Huang³

et al. 2019

SN Appl. Sci.

View full text Add to dashboard Cite

show abstract

“…However, with the AN‐MAN combination, dramatic changes in the size were not detected. Previous research has shown that particle size varies with several parameters such as the presence of certain monomers and core materials . It has also been reported that preparation process parameters can influence the final capsule size and size distribution; the main factors are polymerization conditions such as polymer reaction temperature, chemical structure of shell materials, structure of the reactor, agitation speed, and pH .…”

Section: Resultsmentioning

confidence: 99%

“…The mixture was polymerized at 60 °C and 1500 rpm for 8 h. After polymerization, the particles were washed with water several times, and the suspending agent was removed from the particles by stirring with acetic acid. Finally, the resultant was filtered and dried at ambient temperature for 48 h . Dried FMs were mixed with epoxy resin in order to prepare the test specimens and conduct further analyses.…”

Section: Methodsmentioning

confidence: 99%

Study on functional microcapsules containing catalysts for controlling the curing time and temperature of epoxy resin

Hwang

Jeoung

et al. 2019

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

In this study, functional microcapsules (FMs) were designed for controlling the curing time and temperature of epoxy through modifications to thermally expandable microcapsules. The FMs were prepared with a mixture of liquid hydrocarbons and N,N‐dimethylbenzylamine in the core, and acrylonitrile (AN)—methyl methacrylate copolymer or AN–methacrylate copolymer were used for the shell. Since the FMs were intentionally designed to have thermally vulnerable polymeric shells, the catalyst in the core could be released at the designated temperature. Therefore, FMs do not activate in epoxy at room temperature; rather, the FMs only become functional when the epoxy is cured under a heated atmosphere. Released catalyst at the higher temperature was confirmed by pyrolysis gas chromatography–mass spectrometry and optical microscopy. This study shows that the results will depend on the different compositions of liquid hydrocarbons and catalyst. Particle size of the capsules was changed with different ratio of catalyst and liquid hydrocarbon at the core and type of polymeric shell. Differential scanning calorimetry and rheometer results showed that higher catalyst loading resulted lower in crystalline and shear thickening temperature, respectively. Adhesion strength of epoxy containing FMs was analyzed by lap shear strength in order to detect the void effect due to released gas from the FM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47499.

show abstract

“…The results plotted in Figure 8 could provide an approach to obtain the encapsulated content of alkane. 25,29,35,40 However, this value of Group 2 could not be obtained from the T g curve in Figure 8(b). The larger particle diameter of Group 2 and the small volume of the crucible caused the overflow of expanded TEMs, which led to the rapid reduction in this curve.…”

Section: Encapsulated Content Of Alkane Of Temsmentioning

confidence: 91%

Preparation of small particle diameter thermally expandable microspheres under atmospheric pressure for potential utilization in wood

Zhang

et al. 2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

Small particle diameter thermally expandable microspheres (TEMs) were obtained for potential utilization in wood, with special attention on their particle diameters and expansion properties. The revolving speed of homogenization (RS) of 800~3000 r min −1 was applied in suspension polymerization under atmospheric pressure to prepare TEMs, with n-hexane as core material and the copolymer of acrylonitrile, methyl acrylate, and vinyl acetate as shell. (a) The effect of the RS on the particle diameters of TEMs presented a negative correlation at low RS and remained stable at high RS, (b) When the RS was 1900~2100 r min −1 , the optimized TEMs with average particle diameters of 3.82~4.06 μm were prepared, possessing expansion ratios of 3.4~4.3 and an expansion temperature of 112 C, (c)The optimized TEMs had core-shell structure and high encapsulated content of alkane, and (d) The TEMs with small particle diameters could be impregnated into wood and expand successfully in wood cell lumens.

show abstract

Fabrication of thermally expandable core–shell microcapsules using organic and inorganic stabilizers and their application

Cited by 15 publications

References 18 publications

Synthesis and characterization of high temperature resistant thermal expansion microsopheres with P(acrylonitrile/methacrylic acid/N,N-dimethylacrylamide/n-butylacrylate) shell

Synthesis and characterization of high temperature resistant thermal expansion microsopheres with P(acrylonitrile/methacrylic acid/N,N-dimethylacrylamide/n-butylacrylate) shell

Study on functional microcapsules containing catalysts for controlling the curing time and temperature of epoxy resin

Preparation of small particle diameter thermally expandable microspheres under atmospheric pressure for potential utilization in wood

Contact Info

Product

Resources

About