التعاون

فنون

الجمال والعناية

حِرَف

الثقافة والتاريخ

ترفيه

البيئة

الطعام والمشروبات

الهندسة العكسية

العلوم

رياضة

التقنية

الأجهزة القابلة للارتداء

PTFE Fine Powder: a Dispersion Stirred Until It Curdles (Lontz 1952)

أنشأه

Charlie

28. أكتوبر 2026

PTFE Fine Powder: a Dispersion Stirred Until It Curdles (Lontz 1952)

A PTFE dispersion is stable on the shelf, but stirred hard enough it curdles. Fifty seconds at 1000 rpm in a baffled beaker and the polymer floats up as a dry-looking, unwettable crumb. Washed and dried, it is a free-flowing powder for rolling into tape, or for cold lubricated extrusion. Source: J. F. Lontz (du Pont), US 2,593,583 (1952), Example 1. Lontz started from a dispersion made with disuccinic acid peroxide; ours is Berry's persulfate dispersion, diluted to his 17 %. Picture drawn by Youblob.

متوسط

1 day

التعليمات

Dilute the dispersion to 17 %

Ours: stir the 34 % dispersion with an equal weight of distilled water to get 17 % solids, the strength Lontz used.

المواد لهذه الخطوة:

مُشتَّت PTFE المائي1 part

ماء مقطر1 part

الأدوات المطلوبة:

ميزان ذو كفّتين

مرطبانات زجاجية بأغطية

Set up the baffled beaker

A 1-gallon stainless beaker, 6.5 in across and 7.5 in deep, with four baffles about ⅜ × 1 in hanging from the cover to within 3 in of the bottom. Stirrer: open turbine, 4 blades 1½ in high, 5 in across, reaching to within 1 in of the bottom.

الأدوات المطلوبة:

خزان تقليب بحواجز

محرّك تقليب

Stir hard at 176 °F for 50 seconds

Put in half a gallon of the 17 % dispersion and heat it to 176 °F (80 °C). Run the stirrer at 1000 rpm for 50 seconds (Lontz measured 0.72 hp per gallon). The polymer coagulates and floats, unwetted, on top.

الأدوات المطلوبة:

خزان تقليب بحواجز

محرّك تقليب

صفيحة تسخين

ميزان حرارة

Wash hot, then cold

Pour off the water. Wash the polymer with hot water at 176 °F, then with cold water at 60 °F (16 °C), and drain.

الأدوات المطلوبة:

خزان تقليب بحواجز

ميزان حرارة

Dry at 230 °F for 16 hours

Spread the wet polymer on a 100-mesh screen and dry it in an oven at 230 °F (110 °C) for 16 hours. It comes out a free-flowing granular powder that passes 6–8 mesh.

الأدوات المطلوبة: