Recycling of PC and ABS From E-waste

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Recycling of ABS and PC from electrical and electronic waste.Effect of miscibility and previous degradation

on final performance of industrial blends

Rafael Balart a,*, Juan Lopez a, David Garcıa a, M. Dolores Salvador a,b

a Mechanical and Materials Engineering Department, Polytechnic University of Valencia, Paseo del Viaducto 1,

03801 Alcoy, Alicante, Spainb Mechanical and Materials Engineering Department, Polytechnic University of Valencia, Camino de Vera s/n, 46022 Valencia, Spain

Received 14 October 2004; received in revised form 31 March 2005; accepted 1 April 2005

Available online 24 May 2005

Abstract

The aim of this work, within the framework of polymer recycling, is to upgrade waste from electrical and electronic

equipment. Blends of the two major residues were prepared via a melt blending process. These are ABS consisting of a

SAN thermoplastic matrix with a dispersed elastomeric (polybutadiene rubber) component and polycarbonate (PC).

The effect of partial miscibility and previous degradation levels was investigated. Mechanical characterization of

ABS/PC systems was carried out to determine the optimum composition range. Previous degradation levels of the

two wastes were investigated by FTIR and little degradation was found on ABS due to the presence of a polybutadienerubber which is more sensitive to thermo-oxidative processes but no significant degradation was found on PC. Differ-

ential scanning calorimetry (DSC) tests demonstrated certain miscibility between the two components by identifying

two glass transition temperatures. This partial miscibility, together with the small degradation of the elastomeric com-

ponent, contributes to a low interaction promoting a decrease on mechanical performance. Scanning electron micro-

graphs (SEM) showed the system morphology and certain lack of adherence along SAN/polybutadiene interface

related to degradation of polybutadiene spheres which act as stress concentrators. The use of the equivalent box model

(EBM) allowed to quantify the interaction level by determining an interaction/adherence parameter ‘‘ A’’, which turned

to be lower than 1 and corroborated the lack of interaction.

Ó 2005 Elsevier Ltd. All rights reserved.

Keywords: Recycling; Blends; Mechanical properties; Mechanical models

1. Introduction

Analysis of polymer alloys and blends has become a

special field of research on polymeric materials recycling,

since separation processes of the different industrial

wastes can be very complex and expensive [1]. Some sep-

aration processes based on physical and chemical proper-

ties of materials have been proposed [2,3] but they are

difficult to be applied at industrial level in most cases.

Otherwise we have to take into account that most of

these wastes (mainly engineering and high performance

plastics) maintain an excellent balance in properties

0014-3057/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.

doi:10.1016/j.eurpolymj.2005.04.001

* Corresponding author. Tel.: +34 96 652 84 21; fax: +34 96

652 84 78.

E-mail address: [email protected] (R. Balart).

EUROPEAN

POLYMER

JOURNALEuropean Polymer Journal 41 (2005) 2150–2160

www.elsevier.com/locate/europolj

mailto:[email protected]

mailto:[email protected]



and they can be directly recycled by using different types

of reinforcements to improve mechanical properties [4].

Recycling of different wastes by blending techniques

is a feasible solution for most engineering plastic wastes,

as in the case of ABS and polycarbonate (PC) coming

from electrical and electronic equipment (WEEE).

ABS/PC mixtures are quite complex since the systemcan be considered as a physical blend of two materials

with different nature: a high toughness homopolymer,

PC, and a great consumption material, such as ABS,

which consists of a poly(styrene-acrylonitrile) (24 wt%

acrylonitrile) block copolymer (SAN) matrix in which

polybutadiene spheres of elastomeric nature are dis-

persed. But in addition to the academic interest in this

system, there exists an industrial interest not only for

WEEE but also for automotive wastes [5,6] and then,

we have to be able to relate microscopic properties with

macroscopic ones (mainly mechanical properties), since

this will allow to undertake recycling and upgradingprocesses for these wastes.

It is not necessary that a recycled material would

show the same properties than virgin resins. Neverthe-

less, a good balance between properties and process-

ability which allows its reuse and upgrading is

absolutely necessary in a recycled material. Blending

techniques are an interesting solution to obtain syner-

getic properties and upgrade polymer wastes but they

are limited by compatibility considerations. Compati-

bility is an often poorly defined qualitative term and

it can drive to different interpretations. Therefore, it

is possible to process these materials for the whole

compositions range and obtain a homogeneous mate-

rial from a macroscopic point of view with no discon-

tinuities on blend morphology; but, on the other hand,

the presence of two different glass transition tempera-

tures (T g) shows a typical sign of an immiscible or par-

tially miscible system. The relationship between T gchanges and macroscopic behaviour of blends can

drive, in certain cases, to contradictory results. Some

partially miscible systems that show large T g changes,

which are indicative of high interactions and as a con-

sequence high solubility, show mechanical properties

below the additivity rule (PVC/PS system), while sys-

tems with lower T g changes, and consequently lowersolubility, show changes in tensile strength with com-

position almost corresponding to additivity such as

for PMMA/PS blends [7].

2. Experimental

2.1. Materials

Polycarbonate (PC) and ABS wastes were provided

by ACTECO S.A (Alcoy, Spain) coming from electrical

and electronic equipment. Both materials were charac-

terized and the obtained results for MFI, density and

VST were as follows. For polycarbonate waste: MFI

(230 °C/5 kg) = 6.06; density = 1.2 g/cm3; VST = 139.2

°C. For ABS waste: MFI (230 °C/5 kg) = 20.45; den-

sity = 1.05 g/cm3; VST = 95.3 °C.

2.2. Blends and sample preparation

In order to obtain an optimum blending process, PC

and ABS wastes, in pellet form, were respectively dried

in vacuum at 120 °C and 80 °C during 4 h. Later, they

were mixed by using a screw extruder at 220 °C and

then, samples for different mechanical tests were pre-

pared by an injection moulding process on a Sandretto

30 lm (Sandretto UK Limited, Warwickshire, England).

Injection speed varied in the range 25–32 cm3/s depend-

ing on the blend composition and temperature in the

injection point was varied in the range 240–290 °C for

ABS and PC based compositions, respectively. Injectionpressure was maintained in the range 1700–1800 bar. We

used a mould with normalized samples dimensions for

tensile and impact tests according ISO-527 and ISO-179.

2.3. Measurements of previous degradation level

As both ABS and PC are especially sensitive to ther-

mo-oxidative processes, identification of degradation

species achieves great relevance. By infrared spectros-

copy we compared spectra for recycled and virgin mate-

rials to estimate degradation levels accumulated by both

materials during their pre-processing and service life.

Fourier transformed infrared spectroscopy (FTIR) mea-

surements were carried out with a Mattson Satellite 3000

spectrometer (Thermo Electron Corporation, Erlangen,

Germany). The thin films were prepared by solution

with dichloroethane and dried to remove all solvent

traces.

2.4. Differential scanning calorimetry measurements

Miscibility of the different components of ABS/PC

system was studied through the changes on glass transi-

tion temperature (T g) by using a Mettler-Toledo 821

DSC (Mettler Toledo Inc., Schwarzenbach, Switzer-land). 5–7 mg samples were subjected to a first heating

(30–160 °C at 10 °C/min) followed by a slow cooling

to remove thermal history and were heated again (30–

250 °C at 10 °C/min) until degradation. Measurements

of glass transition temperature were made on the second

heating curve.

2.5. Mechanical properties

Mechanical properties were determined by means

of a universal tensile test machine ELIB 30 (S.A.E.

Ibertest, Madrid, Spain) following ISO-527. Impact

R. Balart et al. / European Polymer Journal 41 (2005) 2150–2160 2151



energy was determined by using Charpy method

(S.A.E. Ibertest, Madrid, Spain) according to ISO-

179 standard.

2.6. Scanning electron microscopy (SEM) measurements

Morphology studies of the fracture surfaces of thedifferent blend compositions were carried out by means

of a scanning electron microscope JEOL JSM-6300

(JEOL USA Inc., Peabody, USA). Coating process

was performed in vacuum conditions. In addition, en-

ergy dispersive X-ray analysis (EDX) was carried out

with a microprobe (Link Pentafed, Oxford Instruments)

for qualitative analysis of fracture surfaces.

2.7. Other techniques

MFI measurements were obtained with a extrusion

plastometer (Ats Faar S.p.A, Vignate, Italy) accordingto the guidelines of ISO-1133 and Vicat softening tem-

perature (VST) measurements were made on a standard

Vicat/HDT station DEFLEX 687-A2 (Metrotec S.A.,

San Sebastian, Spain) following ISO-306.

3. Results and discussion

3.1. Previous degradation levels of ABS and PC wastes

As we are working with wastes, a previous degrada-

tion study is relevant as degradation accumulated by

both materials can condition their final performance.FTIR spectra for both ABS and PC wastes were

compared with virgin ABS and PC spectra to estimate

differences. We could appreciate small degradation

in ABS identified by the presence of hydroxyl

groups which absorb near 3250 cmÀ1 (Fig. 1). The

absence of carbonyl groups (which absorb around

1750 cmÀ1), which appear as a result of high thermo-

oxidative degradation levels, indicates that previous

degradation levels on ABS are not significant and they

will not condition significantly the final performance of

blends.

Regarding the PC resin (Fig. 2), although it ishighly sensitive to hydrolysis and thermo- and photo-

oxidative processes, its FTIR spectrum shows no degra-

dation peaks and this indicates the good quality of the

waste.

Fig. 1. Comparison between FTIR spectra of (a) recycled ABS and (b) a commercial (Polylac PA-714C) virgin ABS resin.

2152 R. Balart et al. / European Polymer Journal 41 (2005) 2150–2160



3.2. Miscibility of ABS/PC system

Observations on some PC/styrene copolymers were

used to estimate interaction energies between binary

pairs using the Flory–Huggins theory, where composi-

tion of the styrenic copolymer (mainly acrylonitrile con-

tent), and the nature of the polycarbonate resin are

decisive on the miscibility study. In the different calori-

metric analysis we obtained systems with only one T g,

systems on which PC shows evidence of certain crystal-

line zones, but the most common situation is that the

different blends show partial miscibility [8–11].

Our study has focussed on the analysis of bisphenol-A, PC homopolymer and ABS with a SAN matrix and

an elastomeric component dispersed in spherical form.

Both materials were subjected to a previous processing

cycle and they were exposed to degradation conditions

during service life. In this work we analysed thermal

behaviour of blends in order to relate macroscopic prop-

erties with microscopic behaviour. As we are working

with amorphous materials, information about interac-

tion phenomena between components is restricted to

the study of changes on T g since the system does not

show melting peaks which allow to observe annealing

effects typical of PC, such in blends with poly(ethyl-

ene-terephthalate) [12], effects that can influence on

mechanical properties.

Regarding changes on T g values, we can observe that

ABS/PC system displays two glass transitions for all the

compositions range. The dependence with the composi-

tion indicates certain interaction between components.

If the system is immiscible, T g values of individual poly-

mers would not change; otherwise if the system is com-

pletely miscible, it would display only one T g. ABS/PC

system shows an intermediate behaviour, since we can

observe two changing T g values in the whole composi-

tion range (Fig. 3). When compared to similar styrenic

blends with amorphous materials, changes on T g of ABS are near 10 °C (Table 1), which are similar to val-

ues obtained in PS/PVC system and higher than

PMMA/PS and PMMA/SAN systems where T g changes

are near 2–4 °C [13].

This partial miscibility does not imply a phase differ-

entiation but we obtained a material with the coexis-

tence of PC rich zones with some ABS chains included

there [14] (mainly SAN chains with low molecular

weight) and ABS rich zones characterized by the pres-

ence of some PC chains included in the SAN matrix.

Furthermore, the different changes on T g values of the

PC and the ABS rich phase gives some information

Fig. 2. Comparison between FTIR spectra of (a) recycled PC and (b) a commercial (Trirex 3122/3022) virgin PC resin.




about the system. While T g of the PC rich phase changes

in the whole range, T g of the ABS rich phase remains

constant up to 0.4 volume fraction of PC and then starts

increasing with PC content.

Many authors [8,9] used the equation proposed by

Fox, with certain changes, to determine the relationship

between the T g of a blend and the composition of the

different phases.

1

T g ¼

w1

T g1 þ

w2

T g2 ð1Þ

The previous equation is useful to determine T g of a

blend by knowing the weight fraction of each compo-

nent and their respective T g. It is possible to determine

compositions of the conjugated phases by making some

arranges on Eq. (1), and then, the following equations

are derived:

w02 ¼

T g2 Á ðT g1 À T 0gÞ

T 0g Á ðT g1 À T g2Þð2Þ

w001 ¼

T g1 Á ðT g À T 2Þ

T g Á ðT g1 À T g2Þð3Þ

where w, weight fraction; 1, sub-index referred to PC; 2,

sub-index referred to SAN; 0, super-index referred to PC

rich conjugated phase; 00, super-index referred to SAN

rich conjugated phase.

Values of T g for PC and SAN rich phases can help us

to determine weight and volume fractions of each phase,

according to the previous equations, referred only to

miscible components (PC and SAN) since butadiene

phase does not take part in miscibility phenomena

because of its net structure (Figs. 4 and 5). These results

are consistent with those obtained in other studies car-

ried out with PC/SAN and PC/ABS blends [8,10,11].Observation of Figs. 4 and 5 is useful to conclude that

PC is able to contain higher SAN amounts, basically

due to the presence of low molecular weight species on

SAN as a result of a small previous degradation during

pre-processing and service life [14].

0.0 0.2 0.4 0.6 0.8 1.0

380

390

400

410

420

T g

V a l u e s

( K )

PC weight fraction

ABS rich phase

PC rich phase

Fig. 3. Changes on T g values for ABS and PC rich phases.

Table 1Variation of glass transition temperatures for the SAN and PC

rich phases with different ABS/PC blends compositions

ABS wt% T 00 g (SAN rich phase) [K] T 0 g (PC rich phase) [K]

100 377.4 –

90 377.6 399.4

80 377.6 400.3

70 379.8 403.1

60 377.8 404.1

40 380.2 408.5

30 383.0 410.0

20 384.1 414.2

10 385.5 418.9

0 – 419.1

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

PCABS

v'1

v'2

v o l u m e f r a c

t i o n

PC wt%

Fig. 4. Plots of PC rich phase composition vs blend compo-

sition based on changes of glass transition temperature.

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

PCABS

v"1

v"2

v o l u m e f r a c t i o n

PC wt%

Fig. 5. Plots of SAN rich phase composition vs blend compo-

sition based on changes of glass transition temperature.






appropriate for polymer blends that show low mechan-

ical performance.

EBM considers that certain fractions of each material

contribute to mechanical properties as in series work,

while other fractions contribute in parallel and can be

used to predict the tensile strength of a blend by making

some considerations. In this case, due to the relevance of

interfacial phenomena on mechanical properties [10,15–

17,19], the model allows to estimate the ranges on which

tensile strength of blends can be found. When the

Fig. 7. (a) SEM micrograph of the fractured surface of a 60ABS/40PC wt%, (·5000). (b) EDX analysis of different points in the

fractured surface.




adhesion/interaction force along the interface is very

low, the coupling in series does not contribute to the sys-

tem resistance, and then tensile stress is only defined by

the parallel coupling.

r RðminÞ ¼ r1 Á v1p þ r2 Á v2p þ A Á minðr1;r2Þ Á vs ð4Þ

In this expression, A is an experimental parameter

related to the intensity of the adhesion/interaction forces

along the interface [8,18]. Low A values are representa-

tive of low adhesion/interaction along the phases and

A values close to 1 are representative of high

interactions.

The main problem for the application of this model is

the calculation of the system parameters; in this case,

designed by vij (i : component, j : working way, series or

parallel). An interesting approach is the use of the criti-

cal values defined by a general theory for multiphase sys-

tems, such as percolation theory [20–24] which has given

good results in many polymeric systems [25–28]. These

parameters can be calculated as follows:

v1p ¼v1 À v1crit

1 À v1crit

T 1

ð5Þ

v2p ¼v2 À v2crit

1 À v2crit

T 2

ð6Þ

where vcrit is the percolation threshold representing the

critical volume fraction that promotes an important

change in behaviour, and T represents the critical expo-

nent related to the geometry of the property variations

as described in the general equation proposed by the

percolation theory.

P / ðv À vcritÞT ð7Þ

This equation suggests that a certain property, P , in a

multiphase system is directly related to the volume frac-

tion of one component, v, regarding to a critical value,

vcrit, which represents the minimum volume fraction to

accomplish certain property. This geometry is affected

by a critical exponent, T , related to the system

behaviour.

According to Eqs. (5) and (6), the determination of

series and parallel fractions for each component in the

blend depends on the critical values defined by percola-tion theory, vcrit and T (percolation threshold and criti-

cal exponent, respectively). Therefore, prediction of

mechanical properties is based on the determination of

these critical values by identifying the most appropriate

lattice structure for the system (square, triangular, hex-

agonal, 3D lattices . . .). Many studies have focussed on

the determination of these critical values and generally,

values based on three-dimensional geometries give good

results, especially in heterogeneous isotropic materials

[23]. Therefore, for three-dimensional domains of spher-

ical type of discrete nature, percolation theory estab-

lishes percolation threshold vcrit = 0.156, while value of

the universal exponent, T , is located in the range

1.7 < T < 1.9. Many systems use T = 1.8 with excellent

results [14,18,29–31]. These values remain constant in

this work, since it will permit to estimate the interaction

phenomena along the interface, and this allows knowing

much more about the system structure. The evolution of

the volume fractions that contribute in series or in par-allel (Fig. 8) shows an interesting behaviour, which is re-

lated to the partial miscibility of the ABS/PC system. We

can appreciate a co-continuous zone in the range 82–

14 wt% of ABS. The same behaviour was observed in

other blends based on glassy and also on semi-crystalline

polymers [22].

Out of the co-continuous range (v1 < v1crit and

v1 > 1 À v2crit), mechanical characteristics are defined

by the major component. Nevertheless, we can observe

a small decrease on properties due to the inclusion effect

that the minor component exerts to the system. The min-

or component acts as a stress concentrator because of the low interaction in this range. As we can observe in

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

PCABS

vp

v1p

v2p

p a r a l l e l w

o r k i n g v o l u m e f r a c t i o n

PC wt%

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

PCABS

s e r i e s w o r k i n g v o l u m

e f r a c t i o n

% peso PC

vs

v1s

v2s

a

b

Fig. 8. Plots of variation of (a) parallel working fractions and

(b) series working fractions, by using Equivalent Box Model

(EBM), for different PC wt%.




Fig. 8, while series fractions follow a similar evolution in

both materials, the parallel fraction, which is mainly

responsible of the system stiffness, is directly related to

the weight fraction of each component (always in the

co-continuity range).

The use of EBM to predict Young modulus is not

necessary since both materials show similar values, closeto 1750–1760 MPa. As a consequence, Young modulus

of the different blend compositions fit perfectly in this

range. The use of EBM to predict tensile stress is more

useful; it gives more information about phase interaction

since we can find a big difference on tensile stress values.

As it has been previously described, it is possible to

determine A value which is related to interaction/adhe-

sion phenomena.

Results obtained for tensile stress largely depend on

interaction/adhesion along the interface, as described

in Eq. (4). The use of EBM allows to obtain a range

where we can find tensile strength values of blends. Thisrange is defined by the upper limit (A values close to 1

which is related to good interaction along phases and

consequently, good load transmission) and the lower

limit characterized by an absolute lack of interaction

which leads to A values close to 0 (poor load transmis-

sion) and then, the dispersed phase acts as a stress con-

centrator promoting an early fracture.

Fig. 9 shows different curves with the critical values

previously defined and different A values. As we can

observe, if there is a maximum interaction (A = 1) the

system behaviour is described by the Mixtures Rule;

we can appreciate a linear behaviour. Nevertheless, as

A values are lower we can observe a significant decrease

on tensile strength, especially in the co-continuous

range. As can be observed in Fig. 9, the evolution of

curves is similar for different A values. The only differ-

ence is the bending in the central range. High A values,

related to a good interaction, induce low curvature and

low A values promote an important curvature because

of the lack of interaction. Similar behaviour was found

in other polymeric blends which does not show a syner-

getic behaviour [18,22].

As we can expect, experimental results for tensile

strength are inside the range defined by the upper and

lower limit (A = 1 and A = 0, respectively) obtained byusing EBM. These results allow to know much more

about the system structure by comparing experimental

data with the different curves (represented by different

A values) and determining which one fits more accu-

rately with experimental results. As we can observe,

experimental data do not fit the A = 1 curve, so a certain

but not maximum interaction along the interface can be

expected. The curve that better fits experimental data is

that for A close to 0.75. These results corroborate the sit-

uation that has been previously described in the fracture

analysis of different ABS/PC samples; a fragile fracture

was observed, with evidence of certain lack of adherence

in some areas corresponding to the elastomeric phase,

since polybutadiene is more sensitive to thermo-oxida-

tive processes related to the polyenic chain, which are

to a large extent responsible of this lack of interaction.

This situation, together with the absence of miscibility

between the polybutadiene phase and the rest of compo-

nents (SAN and PC) intensifies the behaviour of polybu-

tadiene spheres as stress concentrators which promote

fracture (Fig. 10).

All these results indicate certain adherence along

the components that constitute the blend, which is

enough to prepare materials with acceptable proper-

ties at industrial level. This optimum range is com-

prised between 10 and 20 wt% of PC. In this range,

mechanical properties are quite interesting and we

can observe a small decrease on tensile strength and

elongation at break, while stiffness remains constant.

This composition range is really interesting for two

reasons: firstly, it allows to obtain materials with

appropriate properties to be used in different industrial

areas as engineering plastics and secondly, this range

is similar to the generation ratio of these wastes which

is close to 4:1 for ABS and PC, respectively. The highABS content allows an easy transformation by using

similar temperatures to those used for styrenic deriva-

tives.

4. Conclusions

Blends based on ABS and PC wastes from electrical

and electronic equipment show interesting properties.

We can observe a decrease on mechanical properties

when compared with virgin materials but this does

not limit their use as engineering plastics since their

0 20 40 60 80 100

16

24

32

40

48

56

PCABS

EBM (A=1)

EBM (A=0.75)

EBM (A=0.50)

EBM (A=0.25)

EBM (A=0)

Experimental data

T e n s i l e s t r e n g

t h ( M P a )

PC wt%

Fig. 9. Variation of tensile strength with ABS/PC blends

composition compared with predicted values based on EBM

by using percolation parameters, v1crit = v2crit = 0.159 and

T 1 = T 2 = 1.8.




performances are still higher to most commodities and

even some engineering plastics.

Compositions in the range 20–80 wt% PC are charac-

terized by an important decrease in both, mechanical

resistant and ductile properties. Efforts must be focussed

in the improvement of the blend homogeneity with an

increase on the interaction between components in the

interface. The use of small amounts of modified nano-

clays gives good results since they act as compatibilizers

improving the phase interaction and as a consequence,

an important increase on performance.

The composition range comprised between 10 and

20 wt% PC is most interesting in order to obtain anindustrial material with balanced properties, for differ-

ent reasons: firstly, mechanical ductile properties do

not decrease. Secondly, processing conditions are similar

to other styrenic derivatives and finally, this composition

range reflects the generation ratio of these wastes which

is close to 4:1 for ABS/PC.

A decrease on mechanical properties can be attrib-

uted to different phenomena. First of all, previous degra-

dation on materials can be the responsible of this

decrease. The presence of an elastomeric phase (a poly-

butadiene rubber dispersed in a SAN matrix), which is

especially sensitive to thermo-oxidative degradation, is

one of the most influencing factors on final performance

since its degradation promotes a decrease on adherence

with the SAN matrix acting as stress concentrators.

On the other hand, ABS/PC system shows partial

miscibility and this situation can exert the same effect

with the elastomeric phase. We found a SAN rich phase

which is not completely miscible with a PC rich phase

and the lack of adherence between these two conju-

gated phases can influence negatively on mechanical

performance.

It is possible to conclude that extrusion and injection

moulding processes are effective enough to obtain homo-

geneous blends since heating processes ensure good mix-ing conditions and final macroscopic homogeneity. In

this case, blends based on two amorphous polymers with

similar rheological behaviour processed by injection

moulding followed by a quick cooling will not allow a

phase separation, and we will obtain a false compatibil-

ity effect, but the lack of miscibility will be observed

both by the presence of two different T g and lower

mechanical properties.

The importance of T g variation is not indicative of a

good compatibility since this variation can be explained

by simple physical phenomena. The low T g polymer will

slowly increase its T g with the other polymer content

Fig. 10. SEM micrographs of the fractured surface of different ABS/PC blends sowing polybutadiene spheres as stress concentrators,

·5000. (a) ABS 90/PC 10 wt%, (b) ABS 85/PC 15 wt%, (c) ABS 70/PC 30 wt%, and (d) ABS 40/PC 60 wt%.




since it will be surrounded by the high T g polymer

chains. On the other hand, when the high T g polymer

reaches its T g value, it will be surrounded by the low

T g polymer chains in a plastic state, and then, even by

low ratios, its presence will enable high T g polymer

chains movement.

Regarding the use of predictive models, EquivalentBox Model (EBM), widely used to explain many poly-

meric and composites systems, gives good results and

contributes to corroborate some hypothesis based on

the partial miscibility and low interaction along the

interface. The application of EBM to ABS/PC system

with usual parameters defined by percolation theory

gives good agreement with experimental data and is use-

ful to corroborate the lack of adherence/interaction

along the interface. The quantification of a parameter

related with interaction showed as A parameter, allows

to estimate the interaction level which is not maximum.

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Recycling of PC and ABS From E-waste