DSC Phân tích nhiệt dành cho các sản phẩm nhựa

Crystal pointTc – Definitionmolecular vibrate and seek for lowest potential energy for crystal arrangement..  Molecular crystal arrangement need energy Time  Molecular crystal arrangem

Thermal analysis applications DSC

-Perkin Elmer DSC

Heat flow change vs temperature

Phase transition (Tg, Tc, Tm) and heat

curing reaction and other chemical reactions

D ifferential S canning C alorimeter

DSC Principle

Glass transition temp.(Tg) – Definition

energy for molecular vibrate.

Waal’s force

energy barrier

PET: Semi-Crystalline Polymer

Semi-Crystalline Polymer

Temp( ℃)

Crystal point(Tc) – Definition

molecular vibrate and seek for lowest potential energy for crystal arrangement. 

△Hc = 115 J/g (for 100% PET crystallization)

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Temp  Molecular crystal arrangement need energy

Time  Molecular crystal arrangement need time

Melting point(Tm) – Definition

higher energy for vibration and throw off the lattice

and become melting state This critical temperature is polymer melting point.

△Hm = △Hc + △Ho

△Ho = △Hm － △ Hc

Cry % = △Ho/115 = (△Hm － △ Hc) / 115

Melting point(Tm) – Spectra

Double Melting Point - Phenomenon

To split another lower Peak (Tm1)

With longer SSPtime, Tm1 will draw close to Tm2

SSP  To form different type.

Crystal type  heat stable type (C1) & dynamic

With longer SSP time, C2 will transform to C1.

The crystal defect has lower Tm2.

With longer SSP, defect be mended, and Tm2

Crystal fragments has lower melting point (Tm2) With longer SSP, fragments grow, and Tm2 draw

Double Melting Point - Dimension

RPET (MSP)

pellets from

extruder

N2 Make-up

Longer SSPtime: only single peak (melting point) Longer SSPtime: high crystallinity (58.3%)

The three sections DSC – Spectra

Crystallization Rate - Cold/Hot Crystal

Decreasing temp.

Increasing temp.

Cold crystal point (Tc1)

Crystal Limited

Melt crystal point (Tc2)

Soft Chain / Plastic agent

Crystal Nuclear

Injection & Blowing Process

Preform

300.00°C at 20.00°C/min PF

2 Cavity 29g PF

Tc1

Moisture Effect : Aging for HR bottle Same batch sample of two preforms

SSP Resin –Normal V.S Abnormal

(yellowlish resin)