Crystalline transitions and related physical properties of poly(dichlorophosphazene)

Harry R. Allcock, Robert A. Arcus

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Highly purified, uncross-linked poly(dichlorophosphazene), (NPCl2)n (II), has been examined by X-ray diffraction, optical, differential scanning calorimetry, and dynamic mechanical techniques. The unstressed polymer is amorphous at 25 °C. Crystallization can be induced by cooling the polymer to -7.2 to -12 °C or by stretching of the polymer at 25 °C. Three different crystalline modifications were detected: lie, crystalline by cooling; IIs, crystalline by stretching; and Ilsr, a metastable crystalline form obtained from the stretched and relaxed polymer. The degree of crystallinity of IIs was 20% and that of Ilsr was calculated to be 11 %. The main crystal melting temperature occurred at +33.1 °C (IIc) or +39 °C (IIs), although the crystallization temperature on cooling is near -7.2 °C. However, additional endothermic transitions were detected at +12 and +25.4 °C for Ilsr. The values detected by use of the dynamic mechanical method differed from those found from X-ray diffraction or differential scanning calorimetry experiments. This anomaly is almost certainly a consequence of the sensitivity of the crystallization behavior of this polymer to stress effects. The physical properties of (NPCl2)n appear to be directly related to the inherent high flexibility of the chain.

Original languageEnglish (US)
Pages (from-to)1130-1136
Number of pages7
JournalMacromolecules
Volume12
Issue number6
DOIs
StatePublished - Jan 1 1979

Fingerprint

Polymers
Physical properties
Crystalline materials
Crystallization
Cooling
Stretching
Differential scanning calorimetry
X ray diffraction
Melting point
Crystals
Experiments
Temperature

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

@article{b0359914ea9b4b75a96eca509004e68b,
title = "Crystalline transitions and related physical properties of poly(dichlorophosphazene)",
abstract = "Highly purified, uncross-linked poly(dichlorophosphazene), (NPCl2)n (II), has been examined by X-ray diffraction, optical, differential scanning calorimetry, and dynamic mechanical techniques. The unstressed polymer is amorphous at 25 °C. Crystallization can be induced by cooling the polymer to -7.2 to -12 °C or by stretching of the polymer at 25 °C. Three different crystalline modifications were detected: lie, crystalline by cooling; IIs, crystalline by stretching; and Ilsr, a metastable crystalline form obtained from the stretched and relaxed polymer. The degree of crystallinity of IIs was 20{\%} and that of Ilsr was calculated to be 11 {\%}. The main crystal melting temperature occurred at +33.1 °C (IIc) or +39 °C (IIs), although the crystallization temperature on cooling is near -7.2 °C. However, additional endothermic transitions were detected at +12 and +25.4 °C for Ilsr. The values detected by use of the dynamic mechanical method differed from those found from X-ray diffraction or differential scanning calorimetry experiments. This anomaly is almost certainly a consequence of the sensitivity of the crystallization behavior of this polymer to stress effects. The physical properties of (NPCl2)n appear to be directly related to the inherent high flexibility of the chain.",
author = "Allcock, {Harry R.} and Arcus, {Robert A.}",
year = "1979",
month = "1",
day = "1",
doi = "10.1021/ma60072a024",
language = "English (US)",
volume = "12",
pages = "1130--1136",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "6",

}

Crystalline transitions and related physical properties of poly(dichlorophosphazene). / Allcock, Harry R.; Arcus, Robert A.

In: Macromolecules, Vol. 12, No. 6, 01.01.1979, p. 1130-1136.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Crystalline transitions and related physical properties of poly(dichlorophosphazene)

AU - Allcock, Harry R.

AU - Arcus, Robert A.

PY - 1979/1/1

Y1 - 1979/1/1

N2 - Highly purified, uncross-linked poly(dichlorophosphazene), (NPCl2)n (II), has been examined by X-ray diffraction, optical, differential scanning calorimetry, and dynamic mechanical techniques. The unstressed polymer is amorphous at 25 °C. Crystallization can be induced by cooling the polymer to -7.2 to -12 °C or by stretching of the polymer at 25 °C. Three different crystalline modifications were detected: lie, crystalline by cooling; IIs, crystalline by stretching; and Ilsr, a metastable crystalline form obtained from the stretched and relaxed polymer. The degree of crystallinity of IIs was 20% and that of Ilsr was calculated to be 11 %. The main crystal melting temperature occurred at +33.1 °C (IIc) or +39 °C (IIs), although the crystallization temperature on cooling is near -7.2 °C. However, additional endothermic transitions were detected at +12 and +25.4 °C for Ilsr. The values detected by use of the dynamic mechanical method differed from those found from X-ray diffraction or differential scanning calorimetry experiments. This anomaly is almost certainly a consequence of the sensitivity of the crystallization behavior of this polymer to stress effects. The physical properties of (NPCl2)n appear to be directly related to the inherent high flexibility of the chain.

AB - Highly purified, uncross-linked poly(dichlorophosphazene), (NPCl2)n (II), has been examined by X-ray diffraction, optical, differential scanning calorimetry, and dynamic mechanical techniques. The unstressed polymer is amorphous at 25 °C. Crystallization can be induced by cooling the polymer to -7.2 to -12 °C or by stretching of the polymer at 25 °C. Three different crystalline modifications were detected: lie, crystalline by cooling; IIs, crystalline by stretching; and Ilsr, a metastable crystalline form obtained from the stretched and relaxed polymer. The degree of crystallinity of IIs was 20% and that of Ilsr was calculated to be 11 %. The main crystal melting temperature occurred at +33.1 °C (IIc) or +39 °C (IIs), although the crystallization temperature on cooling is near -7.2 °C. However, additional endothermic transitions were detected at +12 and +25.4 °C for Ilsr. The values detected by use of the dynamic mechanical method differed from those found from X-ray diffraction or differential scanning calorimetry experiments. This anomaly is almost certainly a consequence of the sensitivity of the crystallization behavior of this polymer to stress effects. The physical properties of (NPCl2)n appear to be directly related to the inherent high flexibility of the chain.

UR - http://www.scopus.com/inward/record.url?scp=0346130693&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0346130693&partnerID=8YFLogxK

U2 - 10.1021/ma60072a024

DO - 10.1021/ma60072a024

M3 - Article

AN - SCOPUS:0346130693

VL - 12

SP - 1130

EP - 1136

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 6

ER -