GB/T 8294-2008 English PDFUS$94.00 · In stock
Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 8294-2008: Natural rubber latex concentrate -- Determination of boric acid content Status: Valid GB/T 8294: Historical versions
Basic dataStandard ID: GB/T 8294-2008 (GB/T8294-2008)Description (Translated English): Natural rubber latex concentrate -- Determination of boric acid content Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: B72 Classification of International Standard: 83.060 Word Count Estimation: 5,574 Date of Issue: 2008-05-15 Date of Implementation: 2008-11-01 Older Standard (superseded by this standard): GB/T 8294-2001 Adopted Standard: ISO 1802-1992, IDT Regulation (derived from): National Standard Approval Announcement 2008 No.8 (Total No.121) Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China Summary: This standard specifies the determination of concentrated natural latex boric acid content. This standard applies to the production of Hevea brasiliensis latex Natural rubber latex concentrate. GB/T 8294-2008: Natural rubber latex concentrate -- Determination of boric acid content---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.Natural rubber latex concentrate. Determination of boric acid content ICS 83.060 B72 National Standards of People's Republic of China GB/T 8294-2008/ISO 1802.1992 Replacing GB/T 8294-2001 Natural rubber latex concentrate Determination of boric acid content (ISO 1802.1992, IDT) Posted 2008-05-15 2008-11-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released ForewordThis standard is identical with ISO 1802.1992 "Natural rubber latex concentrate - Determination of boric acid content" (in English). For ease of use, the editorial changes made the following standard. --- "This International Standard" be replaced by "this standard"; --- Delete foreword international standards; --- References GB/T 8290 sampling in Chapter 6, which is standard with ISO 1802.1992 is no technical difference in the respective sections. This standard replaces GB/T 8294-2001 "Natural rubber latex concentrate - Determination of boric acid content." It was compared to the 2001 edition of this standard and editorial changes. The standard proposed by China Petroleum and Chemical Industry Association. This standard by the National Standardization Technical Committee rubber natural rubber and rubber Technical Committee. This standard was drafted. Chinese Academy of Tropical Agriculture Institute of Agro-band, the Ministry of Agriculture Food Quality Supervision and Testing Center (Zhanjiang). The main drafters of this standard. Lv Mingzhe, more than peace, Chen Chenghai. This standard was first released in July 1987, in July 2001 the first amendment. GB/T 8294-2008/ISO 1802.1992 Natural rubber latex concentrate Determination of boric acid content Warning. Use of this standard shall have a person experiences regular lab work. This standard does not point out all possible security issues. The user's responsibility to take appropriate safety and health practices and to ensure compliance with the conditions relevant national regulations.1 ScopeThis standard specifies the method for determination of concentrated natural latex boric acid content. This standard applies to the Brazilian rubber tree latex production concentrated natural rubber latex.2 Normative referencesThe following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard. However, according to research encourages the parties to the agreement Study whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. GB/T 8290 Natural rubber latex concentrate sampling (GB/T 8290-1987, eqv ISO 123. 1985) Principle 3 Containing boric acid pH is adjusted to approximately 0.02g sample of latex 7.50, then boric acid is substantially non-dissociated state. Then added over The amount of mannitol to form a strongly acidic acid - mannitol complex, thus releasing the equivalent of boric acid in the latex amount of hydrogen ions, the pH value decline. Alkali the pH of the sample return to 7.50, based on the amount of base added boric acid content can be measured.4 ReagentsThis standard uses only recognized analytical reagent, distilled water or water of equivalent purity. 4.1 hydrochloride, mass fraction of 2% solution. 4.2 stabilizer solution, containing a mass fraction of 5% of the ethylene oxide condensate type nonionic stabilizing agent. 4.3 mannitol. 4.4 boric acid solution Weigh about 5g of boric acid (H3BO3), accurate to 1mg, dissolved in water and diluted to 1000mL in a volumetric flask. 4.5 standard solution of sodium hydroxide, Ba (NaOH) ≈0.05mol/L. Calibration solution 4.5.1 Draw 5mL boric acid solution (4.4) with a pipette (5.2) into a 250mL beaker, stabilizer was added 2mL (4.2) and 50mL water. The solution is measured using a pH meter (5.1) the pH, such as pH value of more than 5.5, the edge constantly stirring, hydrochloric acid was added dropwise a solution of (4.1), the pH is reduced to 5.5 to 2.5 range. The solution was allowed to stand 15min, with constant stirring, a burette (5.3) was added sodium hydroxide Solution (4.5) until pH reaches 7.50. Was added and then continued stirring 4g mannitol (4.3), pH value then decreased. From then titrated Tube (5.3) accurately titrated with sodium hydroxide solution, the pH returned to record volume of 7.50 required for sodium hydroxide solution. 4.5.2 Calculation of concentration Sodium hydroxide solution calculated by the formula (1) the concentration of Ba, expressed in moles per liter. Ba = 0.081 × m1 Vp 1 (1) Where. M1 --- 1000mL boric acid solution (4.4) in boric acid mass in grams (g); Vp 1 --- the pH to return to the desired volume of sodium hydroxide solution 7.50 milliliters (mL). 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