FT-IR and FT-Raman studies of cross-linking processes with Ca²⁺ ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch - In moulding sands, Part II.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy · 2015 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 6574

Study snapshot

PublicationSpectrochimica acta. Part A, Molecular and biomolecular spectroscopy · 2015

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

The hardening process of moulding sands on quartz matrices bound by polymer binders containing carboxyl and hydroxyl groups can be carried out by using physical (microwave radiation, thermal holding) and chemical (Ca(2+) cations, glutaraldehyde) cross-linking agents. The highest hardening level obtain moulding sand samples containing binders in a form of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) within the microwave radiation field, for which the bending strength is of 1.6 MPa value even after 24h from ending the agent activity. The authors focused, in this study, on finding the reason of this effect. It was shown, by means of the FT-IR and FT-Raman spectroscopic methods, that the chemical adsorption process activated by microwaves plays an essential role. The applied microwaves activate the polar groups present in the polymer composition structure as well as the quartz crystals surfaces (silane groups). Then the chemical adsorption occurs in the binder-matrix system within the microwave radiation field and intermolecular lattices are formed with a participation of hydrogen bridges (SiOH⋯OC, SiOH⋯OH) and COSi type bonds.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Moulding sand samples with an aqueous PAA/CMS-Na binder hardened within a microwave radiation field showed high bending strength (1.6 MPa) even 24 h after the end of agent activity. FT-IR and FT-Raman results suggested that microwaves activate polar groups in the polymer and silane groups on quartz surfaces, promoting chemical adsorption and formation of hydrogen-bridge networks and COSi-type bonds.

Outcomes measured

Hardening level / bending strength of moulding sand samples
Spectroscopic evidence of chemical adsorption and bond formation (FT-IR, FT-Raman)

Limitations

No microwave frequency, power, or exposure parameters reported in the abstract
No sample size or experimental design details provided in the abstract
Study concerns materials hardening mechanisms rather than biological/health outcomes

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "microwave",
    "source": "microwave radiation field (materials processing)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Hardening level / bending strength of moulding sand samples",
    "Spectroscopic evidence of chemical adsorption and bond formation (FT-IR, FT-Raman)"
  ],
  "main_findings": "Moulding sand samples with an aqueous PAA/CMS-Na binder hardened within a microwave radiation field showed high bending strength (1.6 MPa) even 24 h after the end of agent activity. FT-IR and FT-Raman results suggested that microwaves activate polar groups in the polymer and silane groups on quartz surfaces, promoting chemical adsorption and formation of hydrogen-bridge networks and COSi-type bonds.",
  "effect_direction": "unclear",
  "limitations": [
    "No microwave frequency, power, or exposure parameters reported in the abstract",
    "No sample size or experimental design details provided in the abstract",
    "Study concerns materials hardening mechanisms rather than biological/health outcomes"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "moulding sands",
    "poly(acrylic acid)",
    "carboxymethyl starch",
    "cross-linking",
    "Ca2+",
    "glutaraldehyde",
    "FT-IR",
    "FT-Raman",
    "chemical adsorption",
    "quartz matrix",
    "silane groups"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.saa.2015.06.084
PubMed: 26125981

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