Boric Acid Ph Grade

Catalog NumberACM10043353-5

CAS Number10043-35-3

CategoryBoron Flame Retardant

Description	Under normal conditions, boric acid is stable, free-flowing, and mildly acidic.
Molecular Formula	H3BO3
Purity	99.5% min
Solubility	Solubility in Water +/- 4.7% @ 20°C
Appearance	Granular, Powder
Application	Boric acid is used in the production of agricultural products, flame-retardants, antiseptic treatments, coatings, and metallurgy.
Content	Heavy Metals (as Pb) <20ppm
Notes	Custom powdering as well as custom packaging is available to meet your specifications.
Packaging	50 lb/25 kg
pH	5.10 (1.0% solution 20°C)

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Case Study

Boric Acid as a Synergist for the Synthesis of New Phosphorus-Boron Flame Retardants

Xu, Zhisheng, et al, Journal of Thermal Analysis and Calorimetry, 2018, 133, 1241-1252.

This study successfully synthesized novel phosphorus-boron flame retardants (BPEAs) by incorporating boric acid (BA) into cyclic phosphate acid (PEA) via an esterification reaction. These BPEAs were thoroughly blended with amino resin to produce transparent fire-retardant wood coatings, and the effect of BA addition on coating performance was investigated.
Synthesis of BPEAs
Phosphoric acid (PA) (92.24 g, 0.8 mol) was added to a three-necked flask. Pentaerythritol (PER) (29.95 g, 0.22 mol) and NBA (5.93 g, 0.08 mol) were slowly added to the PA under magnetic stirring and refluxed at 105 °C for 4 h, yielding transparent PEA. Varying mass ratios of BA were then slowly added to the PEA, and the mixture was stirred constantly at 120 °C for 4 h to form BPEAs. Water was removed by reduced-pressure distillation. The PEA:BA mass ratios were 99:1, 98:2, 97:3, and 95:5, corresponding to BPEA1-BPEA4 with 1, 2, 3, and 5 mass% BA, respectively.
Effect of Adding Boric Acid
· Transparency: Decreases gradually with more BA but remains high even at the highest loading.
· Fire Protection & Smoke Suppression: greatly improves. BA significantly reduces: flame spread rating, mass loss, heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke release (TSR), and specific optical density (smoke density).
· Thermal Stability: Improves significantly with more BA (Higher onset decomposition temperature, better high-temperature stability, Greater residual mass).
· Chemical Mechanism (FTIR): BA contributes to forming more phosphorus-rich cross-linked structures and aromatic structures in the char, enhancing flame retardancy and smoke suppression.

Environmentally Friendly Flame-Retardant Wood Coating Made from a Combination of Polysilicate and Boric Acid

Wang, Kaihao, et al. Cellulose, 2021, 28, 11551-11566.

To facilitate the immediate application on previously built wooden structures, a green flame-resistant coating made from sodium polysilicate (SPS) and boric acid was developed.
Key Properties
· The treated wood sample, referred to as SPS/B-wood, exhibited a weight increase of only 10 wt% and achieved a limiting oxygen index (LOI) of 40.3%, successfully earning a V-0 rating in the UL-94 test.
· The SPS/B-wood sample showed reductions in total heat release, total smoke production, and peak carbon monoxide emission by 24.5%, 36.0%, and 59.4%, respectively, compared to the untreated control wood sample.
· According to the thermogravimetric analysis, the residue for the SPS/B-wood sample rose to 54.0% from 18.4% in the control sample at 800 °C.
Flame Retardant Mechanism
SPS and boric acid formed structures containing Si-O-B and Si-O-Si, which helped isolate heat and smoke during combustion. Notably, the presence of NaOH provided by the SPS/B coating facilitated the catalysis of lignin, resulting in the formation of dense, high-quality char.

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