Quantification of dispersion and mixing homogeneity using X-ray profiling

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Comprehensive homogeneity quantification

1LUM GmbH, Berlin, Germany, www.lum-gmbh.com; 2Institut für Angewandte Photonik e.V., Berlin, Germany; 3Beuth Hochschule für Technik BerlinThe Next STEP® in Dispersion Analysis & Material Testing

Scope ExperimentalNanoparticles are often provided as powders and have to be dispersed in different matrices. The resulting state (quality) of dispersion products depends thereby on its dispersibility (nature and quality of raw material), volume concentration, properties of continuous phase and additives, processing (e.g. technology, energy input, time). Beside cost and time, processing should not hamper particle functionality and product stability.

For easy and reliable characterization of dispersibility an algorithm has beendeveloped, which detects inhomogeneities of material distribution by statisticalevaluation and spatially resolved quantification of homogeneity. The inputmeasurement data (transmission) was directly exported from SEPView® softwaremeasured by LUMiReader® X-Ray (LUM, Germany). With X-ray the concentrationof CaCO3 distribution in epoxy was evaluated. As a second example the pigment(ZnO) segregation within intransparent sunscreen lotion was analysed independence of accelerated force.

Homogeneity of fillers dispersed into a polymer matrix

Sample preparation: Epoxy resin L135T + hardener L134 with sample dimensions of 6.5 cm x 1.2 cm 0.2 cm (L x W x T)Filler: CaCO3 mass concentration of 20 %m/mDispersing: mixing of resin and hardener:

mixer speed 3000 rpm for 60 s• good mixing: mixer speed 3000 rpm for 120 s

(sample G1 and G2)• medium mixing: mixer speed 1000 rpm for 60 s

(sample M1 and M2)• bad mixing: slow mixing per hand

(sample S1 and S2) To remove air: 30 min vacuum at 200 mbar (complete removal of air not possible)The samples were prepared by molding and cutting itafterwards.[Müller et al., Dispersion Letters, 2016]

UV blocker homogeneity within opaque sunscreen lotion

Conclusion• Dispersibility is the ability of a given particulate material to be processed to a desired size distribution and/or distributed homogeneously in a continuous phase.• The quantity of this ability is not a single value but depends on, e.g., properties of continuous phase, additives or processing technology, time and energy entry.• It can be efficiently analysed at original concentration (without dilution) by in situ visualization of separation behaviour at earth (LUMiReader®) or elevated gravity (LUMiSizer®).• Fingerprints provide reliable information about dispersion state within a few minutes after processing.• Quantification by extinction/attenuation profiling at the start of separation accessment by LUMiReader® PSA and X-Ray, LUMiFuge® and LUMiSizer® within less than 60 s.• Analysis and operating figures by means of a new, adapted algorithm based on ISO 2578 (e.g. classification and distribution of spikes, Abott plot), turbidity index, PSD as well

as sediment height/packing density.

Acknowledgement We thank Land Berlin, German Ministry of Economy and the European Community for financial support (INNO-KOM-Ost: MF140238 MeBeKo)

2. Step: centrifugation at RCA = 200 – 2300 (LUMiSizer®)

D. Lerche1, A. Zierau2, S. Boldt3, D. Kavianpour1

Cumulative attenuation distribution

cut lin

e of at

ennuat

ion[%

)

fraction of region in %

Rha

Rca

Rlc

Rha Area fraction of high attenuationRca Area core attenuationRla Area fraction of low attenuationAdapted from Ch. Wiehr, J. Seewig, [Script: D-Kenngrößen nach ISO 25178, Univ. Kaiserslautern]

primary original attenuation profilewaviness

corrected attenuation profilestraightend out base line

Figure: Basic steps of homogeneity evaluation. 1. step eliminate waviness, tendency

Cumulative broadness (CB(c)), length fraction of analysed total length of which measured attenuation is above a critical attenuationvalue c (cut line)PB – Peak broadness at critical attenuation c.

100 %

Attenuation profile Abbott curvePB1(c) PB2(c) PB3(c) PBn(c)

Cut line (attenuation)Cumulative braodness CB

attenua

tion [%

]

00,05

0,10,15

0,20,25

0,30,35

0,40,45

0 10 20

Mass

conc

etrati

on in

m/m

Sample height in mm

good dispersion

00,05

0,10,15

0,20,25

0,30,35

0,40,45

0 10 20

Mass

conc

etrati

on in

m/m

Sample height in mm

bad dispersion

00,05

0,10,15

0,20,25

0,30,35

0,40,45

0 10 20

Mass

conc

etrati

on in

m/m

Sample height in mm

medium dispersion

1,39 1,85 7,40813

32

Good medium poorly

Signa

l devi

ation

of

Trans

missi

on [%

]

Dispersibility condition

Standard deviationoptical rating

Spatially resolved mass concentration of CaCO3in 2 mm epoxy resin with average of 20 %m/m CaCO3 measured with LUMiReader® X-Ray and compared with electron microscope

600 g, 30 min, 40°C

2300 g, 30 min, 40°C

2300 g, 3 h, 40°C

1500 g, 30 min, 40°C

200 g, 30 min, 40°C

-0,5

0

0,5

1

1,5

2

0 0,2 0,4 0,6 0,8 1

posit

ional i

nterse

cting

line in

%

Cummulative peak broadness CPB

Homogeneity distribution and segregation of UV blocker in sunscreen lotion

1g_Original168 g_30min_40°C504g_30 min_40°C1344 g_30 min_40°C2300 g_30 min_40°C

Jahrestreffen Dresden 03/2017 - Jahrestreffen der ProcessNet-Fachgruppen Mehrphasenströmungen, Partikelmesstechnik, Zerkleinern und Klassieren, Computational Fluid Dynamics und Mischvorgänge

inhomogenietieswithin

sunscreen

ZnO sediment

less inhomogeneities

STEP 1: STEP 2: STEP 3:

naked eye rating

1. Step: observation by naked eye