GB/T 12010.4-2010Plastics -- Poly (vinyl alcohol) (PVAL) materials -- Part 4: Determination for pH value (English PDF)

Foreword

GB/T 12010 "plastic material polyvinyl alcohol (PVAL)" is divided into eight sections.

--- Part 1. Designation system and basis;

--- Part 2. Performance measurement;

--- Part 3. Specifications;

Part --- Chapter 4. pH value measurement;

--- Part 5. Determination of the average degree of polymerization;

--- Part 6. Determination of particle size;

--- Part 7. Determination of sodium hydroxide;

--- Part 8. Determination of transparency.

This section GB/T Part of 412,010, and JISK6726:1994 (2003 Confirmafion) "Standard Test Method for polyvinyl alcohol" (May Text version) of the non-equivalent.

This Part replaces GB/T 12010.8-1989 "polyvinyl alcohol resin pH value measurement method." this section compared with the GB/T 12010.8-1989 The main changes are as follows.

--- Increasing the reference document (Chapter 2 of this edition);

--- Improve the accuracy of the pH meter (1989 version 5.1, this version 5.1);

--- Improve the accuracy of the balance (1989 version 5.7, this version 5.2);

--- Canceled heated to reflux for sample dissolution (1989 version 6.1, this version 6.1);

--- Sample weight by the sample was adjusted to 12g 15g (1989 version 6.1, this version 6.1).

This part is proposed by the China Petroleum and Chemical Industry Association.

This part of the National Standardization Technical Committee of plastic products and plastic resins General Methods Chapter (SAC/TC15/SC4) centralized.

This section is responsible for drafting unit. Hunan Xiangwei Limited.

This section participated in the drafting unit. China Petrochemical Group of Sichuan Vinylon Works, Ltd. Yunnan Yun-dimensional, synthetic resin national quality supervision Governor Inspection Center.

1 Scope

GB/T 12010 provisions of this section was measured by the method of pH of aqueous solutions of polyvinyl alcohol material with acidity.

This section applies to the determination of pH values \u200b\u200bgreater than 70% alcohol solution (mole fraction) of 4% aqueous solution of polyvinyl alcohol material.

2 Normative references

The following documents contain provisions which, through reference GB/T 12010 in this section constitute provisions of this section. For dated reference documents Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this section.

GB/T 603 chemical reagent in test methods - Preparations with Laboratory use specifications and test methods GB/T 6682 Analysis GB/T 9724 General rule for determination of pH chemical reagent JJG119-2005 Laboratory pH (acidity) meter Principle 3 Indicator electrode and a reference electrode immersed in the same test solution constituting a primary battery, pH value of the electromotive force and its solution will have specified Off can be derived by measuring the pH of the solution of the original electromotive force.

4 Reagents

When this part of the reagents and water, unless otherwise specified, refer to analytically pure reagents and GB/T 6682 in the third grade water.

Phthalate 4.1 standard buffer solution, according to GB/T 9724 preparation.

Standard 4.2 phosphate buffer solution, according to GB/T 9724 preparation.

Standard 4.3 borate buffer solution, according to GB/T 9724 preparation.

4.4 carbon dioxide-free water, according to GB/T 603 formulation.

5 Instruments

5.1 pH meter. shall comply JJG119-2005 of 4.7 "0.02" requirements.

5.2 Balance. accurate to 0.001g.

5.3 Erlenmeyer flask. 500mL.

5.4 Beaker. 100mL.

5.5 dissolution device. can be heated and stirred.

5.6 Thermometer. Accurate to 1 °C.

6 Steps

Preparation 6.1 4% aqueous solution of polyvinyl alcohol

6.1.1 Weigh a sample of about 15g, accurate to 0.001g, placed in 500mL Erlenmeyer flask.