Epoxy Resins for Flooring Applications, an Optimal Host for Recycling Deactivated Cement Asbestos

Our plain-English summary of Epoxy Resins for Flooring Applications, an Optimal Host for Recycling Deactivated Cement Asbestos, by F. Campanale, F. Vergani, N.M. Marian, et al (Polymers, 2023).

The study

• Authors: F. Campanale, F. Vergani, N.M. Marian, C. Viti, A. Bianchi, S. Ferrario, M. Mauri, G. Capitani
• Journal: Polymers
• Published: 2023;15(6)
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cement asbestos slates, commonly known as Eternit® and still abundant in private and public buildings, were deactivated through a thermal process. The resulting deactivated cement asbestos powder (DCAP), a mixture of Ca-Mg-Al silicates and glass, was compounded with Pavatekno Gold 200 (PT) and Pavafloor H200/E (PF), two different epoxy resins (bisphenol A epichlorohydrin) for flooring applications. The addition of the DCAP filler to the PF samples causes a slight but acceptable decrease in the relevant mechanical properties (compressive, tensile, and flexural strengths) upon increasing DCAP content. The addition of the DCAP filler to pure epoxy (PT resin) causes a slight decrease in the tensile and flexural strengths with increasing DCAP content, while the compressive strength is almost unaffected, and the Shore hardness increases. The main mechanical properties of the PT samples are significantly better than those of the filler-bearing sample of normal production. Overall, these results suggest that DCAP can be advantageously used as filler in addition to, or in substitution for, commercial barite. In particular, the sample with 20 wt% of DCAP is the best performing in terms of compressive, tensile, and flexural strengths, whereas the sample with 30 wt% of DCAP shows the highest Shore hardness, which is an important property to be considered in flooring applications.

In plain English

Cement asbestos slates (Eternit) were heated to about 1100 degrees Celsius and milled into a deactivated cement asbestos powder (DCAP), then lab-tested as a filler in flooring epoxy resins. DCAP was added at 2, 5 and 10 wt% to a barite-containing resin (PF) and at 10, 20 and 30 wt% to a filler-free resin (PT), with DCAP-free comparison samples. In PF, more DCAP tended to slightly worsen mechanical properties. The exception was the 2 wt% sample, an unexplained anomaly with mean tensile strength of about 9 vs 21.6 MPa without DCAP. In PT samples, compressive strength rose from 67 MPa (no DCAP) to about 83.5 MPa (20 wt%), returning to 67 MPa at 30 wt%. Tensile strength fell from about 52 to about 42 MPa, and Shore hardness rose from about 62 to about 85. The authors suggested DCAP can be advantageously used in place of commercial barite and that the 20 wt% PT sample seemed very promising for flooring. They cautioned that the two resins differ, complicating direct comparison. No people or health effects were studied.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory materials experiment: mechanical, hardness, thermal (DSC) and electron microscope (SEM) testing of epoxy resin composites made with a filler derived from heat-treated cement asbestos
• Who was studied: Resin test samples, not people. Two commercial flooring epoxy resins were used: Pavafloor H200/E (PF), which already contains barite filler, and Pavatekno Gold 200 (PT), which has no filler. Samples: PF0, PF2, PF5 and PF10; PT0, PT10, PT20 and PT30. Each mechanical test used at least 4 measurements; hardness used 10 measurements per sample.
• Exposure: Deactivated cement asbestos powder (DCAP): cement asbestos slates heated in air at about 1100 degrees Celsius and ball-milled, giving a mixture of glass and Ca-Mg-Al silicates. The article does not name the specific asbestos fiber types in the slates.
• Main results:
  • In the PF (barite-containing) resin, compressive strength, Young modulus and strain decreased slightly from PF0 to PF5 and PF10, excluding the PF2 sample. The authors summarised that increasing DCAP in PF samples tends to slightly worsen mechanical properties.
  • The PF2 sample (2 wt% DCAP) behaved anomalously. Compared with PF0, its mean tensile strength was about 9 vs 21.6 MPa and its Young modulus 256 vs 614 MPa.
  • In the PT (filler-free) resin, compressive strength rose from 67 MPa (PT0) to about 83.5 MPa (PT20), then returned to 67 MPa (PT30).
  • In PT samples, mean tensile strength fell from about 52 to about 42 MPa as DCAP content increased.
  • In PT samples, flexural strength fell from 74.6 to about 50 MPa as DCAP content increased.
  • In PT samples, Shore hardness rose from about 62 (PT0) to about 85 (PT30). In PF samples, DCAP did not substantially affect hardness, apart from PF2.
  • Adding DCAP did not significantly change the glass transition temperature in either resin.
  • Electron microscope images of fracture surfaces suggested that DCAP adhered to the resin more strongly than barite did.
• The authors' conclusion: The authors suggested that DCAP can be advantageously used as a filler in substitution for commercial barite, and that the PT20 sample (20 wt% DCAP) seemed very promising for flooring applications. They noted that direct comparison between the PF and PT resins is complicated because the resins differ.
• Limitations the authors state:
  • The anomalous behaviour of the PF2 sample remained unexplained.
  • Direct comparison between PF and PT samples is complicated because the two resins differ.
  • Young modulus and deformation values in PT samples varied widely between measurements.

Topics

Medical terms in this study, explained in our Lexicon: Eternit, Silicate, Hardness (Mohs Scale).

Related studies

• Recycling of the product of thermal inertization of cement-asbestos for various industrial applications — A.F. Gualtieri, C. Giacobbe, et al. (2011)
• Microwave polymerisation of epoxy resin: rapid processing technique in ultrastructural pathology — A.L. McLay, J.D. Anderson, et al. (1987)
• Occupational exposure to carbon fibers impregnated with epoxy resins and evaluation of their respirability — P. Lovreglio, A. Stufano, et al. (2020)
• Treatment and recycling of asbestos-cement containing waste — F. Colangelo, R. Cioffi, et al. (2011)
• The transformation sequence of cement-asbestos slates up to 1200 degrees C and safe recycling of the reaction product in stoneware tile mixtures — A.F. Gualtieri, C. Cavenati, et al. (2008)
• Recycling the product of thermal transformation of cement-asbestos for the preparation of calcium sulfoaluminate clinker — A. Viani, A.F. Gualtieri (2013)

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