Mechanical Properties of Microcapsules Used in a Self-Healing Polymer

Abstract

The elastic modulus and failure behavior of poly(urea-formaldehyde) shelled microcapsules were determined through single-capsule compression tests. Capsules were tested both dry and immersed in a fluid isotonic with the encapsulent. The testing of capsules immersed in a fluid had little influence on mechanical behavior in the elastic regime. Elastic modulus of the capsule shell wall was extracted by comparison with a shell theory model for the compression of a fluid filled microcapsule. Average capsule shell wall modulus was 3.7 GPa, regardless of whether the capsule was tested immersed or dry. Microcapsule diameter was found to have a significant effect on failure strength, with smaller capsules sustaining higher loads before failure. Capsule size had no effect on the modulus value determined from comparison with theory.

Self-healing epoxy via epoxy–amine chemistry in dual hollow glass bubbles

“…The cleanness of the HGBs assures that they can carry as much healing agent as possible for selfhealing purpose. maximum displacement relative to the diameter is 8.13 ± 1.11%, which is much lower than that the PUF microcapsule(~ 35% for 63 µm) [35] or the PU microcapsule (~ 11% for 67 µm) [36], and is attributed to the brittle feature of glass. [35], the maximum strength of this etched HGBs is much higher.…”

“…maximum displacement relative to the diameter is 8.13 ± 1.11%, which is much lower than that the PUF microcapsule(~ 35% for 63 µm) [35] or the PU microcapsule (~ 11% for 67 µm) [36], and is attributed to the brittle feature of glass. [35], the maximum strength of this etched HGBs is much higher. And it is twice of the maximum strength of the PU microcapsules (~ 6 MPa) with the similar diameter (~ 70 µm) by Yang et al [36].…”

“…The compressive properties of the etched HGBs with through-holes were conducted using single microsphere compression apparatus as reported by Keller and Sottos [35], and Yang et al [36]. The schematic configuration can be found in the inset in Figure 2a …”

“…Considering the much harsher processing conditions for composite materials, such as repeatedly brushing the adhesive, pressing to remove the excess amount of the adhesive, relatively high post heat-treatment temperature up to hundreds centi-degree, the carriers for the healing agents should be strong enough to survive from the manufacturing of the composites. Keller and Sottos [35] tested the elastic stiffness and the strength of the PUF shell, revealing that the microcapsules with smaller diameter have a higher normalized failure strength while failing at lower loads. Yang et al…”

Self Healing System for Concrete Surface Crack using Polymer based Coating Agent Incorporating Microencapsulated Healing Agent

“…한편, 단순히 균열부의 수동적인 거동을 취급하는 것뿐만 아니라 사전에 콘크리트 배합에 있어 인위적으로 팽창성 혼화재 [6,7] 플라이애시 [8,9] 및 박테리아 [10] 등을 첨가함으로서 자기치유효과를 얻고자 하는 연구가 진행되고 있다. 한편 자기치유성을 재료 에 부여하는 또 다른 방법은 자기치유제를 함유한 마이크로 캡슐 첨가에 의한 자기치유방법이다 [11,12,13,14,15] 마이 크로캡슐에 의한 자기치유 연구는 주로 폴리머 및 합성재료 분야에서 진행되어 왔으며 [13,14,15,16], 최근 콘크리트의 균열부의 자기치유에 적용되고 있다 [17,18] …”