Ultrafast stiffening of concentrated thermoresponsive polymer-mineral suspensions

Published

July 21, 2022

Author(s)

Edward Garboczi, Sharu Kandy, Iman Mehdipour, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Samanvaya Srivastava, Torben Gaedt, Gaurav Sant

Abstract

Extrusion-based 3D printing with rapidly hardening polymeric materials is capable of building almost any conceivable structure. However, concrete, one of the most widely used materials for large-scale structural components, is generally based on inorganic binder materials like Portland cement. Unlike polymeric materials, a lack of precise control of the extent and rate of solidification of cement-based suspensions is a major issue that affects the ability to 3D-print geometrically complex components and large-scale structures. Here, we demonstrate a novel method for controllable-rapid solidification of concentrated polymer-mineral suspensions that contain a polymer binder system based on epoxy and thiol precursors as well as one or more mineral fillers like quartz and calcite. The thermally triggered epoxy-thiol condensation polymerization induces rapid stiffening of the hybrid suspensions (0.30 ≤ ϕ_s ≤ 0.60, ϕ_s = volume fraction of solids), at trigger temperatures ranging between 50 °C to 90 °C achieving stiffening rates up to 400 Pa/s. The use of nucleophilic initiators such as 1-methylimidazole provides control over the activation temperature and curing rate thereby helping to achieve an adjustable induction period and excellent thermal latency. By using multiple techniques including rheology, calorimetry, and flexural strength testing, we provide guidelines to create designer compositions of polymer-mineral suspensions that utilize thermal triggers to achieve thermal latency and ultrafast stiffening – prerequisite attributes for 3D-manufacturing of topologically-optimized structural components.

Citation

ACS Applied Polymer Materials

Volume

221

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.matdes.2022.110905

Local Download

Keywords

ultrafast stiffening, 3D printing, additive manufacturing, thermoresponsive suspensions, epoxy-mineral hybrid suspensions, epoxy-thiol polycondensation, activation energy

Citation

Garboczi, E. , Kandy, S. , Mehdipour, I. , Neithalath, N. , Kumar, A. , Bauchy, M. , Srivastava, S. , Gaedt, T. and Sant, G. (2022), Ultrafast stiffening of concentrated thermoresponsive polymer-mineral suspensions, ACS Applied Polymer Materials, [online], https://doi.org/10.1016/j.matdes.2022.110905, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933463 (Accessed April 28, 2024)