Thomas Murray (Fayetteville State University)

Guangcui Yuan (NCNR) 

Molecular Mass and Composition 

Dependence of Glass Transition 

Temperature in PC/PMMA Blends 
2

•Introduction 

•Materials and Methods

•Results and Discussions

•Summary
3

poly(methyl 

methacrylate) polycarbonate

PC PMMA

Vs

property PC PMMA

Tensile strength 27-75 65-83

Transparency > 88% > 92%

Chemical resistance Strong 

resistance to 

many common 

chemicals 

including acids, 

salt, oil and 

alcohols.

Poor resistance to 

salts. Degrade in 

contact with acid, 

alkalines and 

alcohols. 

Heat Deflection T 127-147oC ≤ 110-115 oC

mechanical Do not crack 

during drilling

Not being scratched 

easily
neutron reflection and 

interfacial diffusion

t = 0 t > 0

PMMA

dPC

asymmetrical interdiffusion and slowdown 

0 20 40 60 80 100

0

1

2

3 (b) 0 min

30 min

150 min

530 min

2300 min SLD5280 min / 10-4 (nm-2)

z (nm)

0 20 40 60 80 100

0

1

2

3 (b) 0 min

90 min

590 min

2195 min

5075 min SLD / 10-4 (nm-2)

z (nm)

4

100% PC blends PMMA 100% 

145 oC

Si air

Si air

PMMA50K

PMMA221K

Si
Polymer Mn

(g/mol)

n (repeat 

unit)

PDI

(polydispersity)

Rg (radius 

of gyration)

Tg

(

oC)

PMMA 4K 3,800 40 1.13 1.6 nm 88

PMMA 50K 50,000 500 1.11 5.7 nm 121

PMMA 221K 221,800 2218 1.16 12.6 nm 127

PMMA 1083K 1,083,000 10830 1.16 26.5 nm 128

dPC 84,000 368 2.41 11 nm 151

5

solution casting

60 oC

vacuum dry 

> 24 hr

solvent

CH2Cl2

PMMA/PC mixture

(85/15; 70/30; 50/50; 

30/70; 15/85)
• Differential scanning calorimetry (DSC)---

determines the temperature and heat flow 

associated with material transitions as a function 

of time and temperature. It also provides 

quantitative and qualitative data on endothermic 

(heat absorption) and exothermic (heat evolution) 

processes of materials during physical transitions 

that are caused by phase changes.

6

Thermal History:

20 oC

200 oC

20 oC

200 oC

88 oC

0.07

0.08

0.09

0.1

0.11

0.12

0.13

60 80 100 120

Heatflow (uV/mg) 

Temperature oC

Glass transition PMMA 4K 

onset

end

mid
7

• There is a single glass transition 

temperature in all blends. 

• The Tgs are shifted from the 

values of 100% PMMA to higher 

with increasing PC content.

• From the above, we conclude 

that the PMMA4K/PC blends are 

miscible over the whole 

composition range.

151 oC
8

• There is a single glass 

transition temperature in blends 

with PMMA50K content >50%, 

indicates these blends are 

completely miscible. • Two distinct glass transitions 

appear in blends with PMMA50K 

content ≤ 50%, indicating partly 

miscibility. 
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• There is a single glass 

transition temperature in blends 

with PC content ≤15 %, indicates 

the blend is miscible. • Two distinct glass transition 

temperatures appear in blends 

with PC content > 15 %, 

indicating partly miscibility. 
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• Two distinct transitions are 

showed in all blends, indicating 

two components are completely 

immiscible. 
• The glass transition and miscibility of polycarbonate (PC) with 

poly(methy1 methacrylate) (PMMA) has been examined using differential 

scanning calorimetry (DSC).

• The Solution casting method has been used to prepare the blends 

with methylene chloride (CH2Cl2) as solvent.

• It is shown that the miscibility for PC/PMMA blends is strongly 

affected by the molecular mass and composition of PMMA.

Blends Miscibility

PMMA4K/PC Miscible over the whole composition range

PMMA50K/PC Partly miscible depending on the composition 

PMMA221K/PC Partly miscible depending on the composition 

PMMA1083K/PC Immiscible at any compositions

11
12

• GUANGCUI YUAN

• MALIA WENNY, JUSCELINO LEAO, TANYA DAX, 

DONNA KALTEYER 

• JULIE BORCHERS, SUSANA TEIXEIRA, LELAND 

HARRIGER

• SURF AND CORE INTERNS 

‘The Center for High Resolution Neutron Scattering (CHRNS) is 

a national user facility jointly funded by the NIST Center for 

Neutron Research (NCNR) and the National Science 

Foundation (NSF) under Agreement No. DMR-2010792.’