Crystallization of Green Poly(Îµ-caprolactone) Nanocomposites with

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Materials and Interfaces

Crystallization of Green Poly(#-caprolactone) Nanocomposites with Starch Nanocrystal: The Nucleation Role Switching of Starch Nanocrystal with Its Surface Acetylation Guorui Zhang, Chunjiang Xu, Defeng Wu, Wenyuan Xie, and Zhifeng Wang Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.8b00514 • Publication Date (Web): 18 Apr 2018 Downloaded from http://pubs.acs.org on April 18, 2018

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Industrial & Engineering Chemistry Research

Crystallization of Green Poly(ε-caprolactone) Nanocomposites with Starch Nanocrystal: The Nucleation Role Switching of Starch Nanocrystal with Its Surface Acetylation Guorui Zhang1 1

Chunjiang Xu1

Defeng Wu1, 2*

Wenyuan Xie1, 2 Zhifeng Wang3

School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu, 225002, China 2

Provincial Key Laboratories of Environmental Engineering & Materials, Yangzhou, Jiangsu, 225002, China 3

*

Testing Center, Yangzhou University, Yangzhou, Jiangsu 225002, China

Corresponding author, Tel: +86-514-87975230, Fax: +86-514-87975244, E-mail address: [email protected] 1

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ABSTRACT Poly(ε-caprolactone) (PCL) was filled with very small amount of starch nanocrystals (SNC), with the objective to control its crystallization. Three kinds of SNC particles, including the pristine one and the acetylated ones with low-level and middle-level substitutions, were used. Their roles acted during PCL crystallization were studied, then. The results reveal that pristine SNC acts as the nucleating agent, increasing crystallization temperature and spherulite growth rate evidently. However, nucleation activity of SNC particles reduces with their increasing level of surface acetylation. The middle-level-acetylated SNC particles even act as the role of antinucleation agent, impeding nucleation and followed spherulite growth of PCL. The phase affinity in those systems was then evaluated by the interaction energy parameter, aiming at better understanding the mechanism of role alterations of SNC particles. This work provides an interesting way to control PCL crystallization, and also opens a new door to extend applications of SNC particles.

Keywords: poly(ε-caprolactone); starch nanocrystal; green composite; compatibility; nucleation.

2


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1. Introduction

Starch is one of the most abundant materials in the world. It is biosynthesized as the semicrystalline granules with densely packed polysaccharides and a small amounts of water. The crystalline and amorphous phase coexist, forming the onion-like structure in granules.

1

The crystalline regions can be isolated by acid hydrolysis or physical

treatments, yielding nanometric particles, namely so-called starch nanocrystal (SNC). 2

Those SNC particles are commonly platelet-like, although their platelet sizes highly

depend on the starch resources. 3 The unique platelet-like structure of SNC, together with its high rigidity, make it promising nanofiller for polymers to improve barrier and mechanical properties. A variety of polymers, including elastomers and plastics, and even the starch-based materials themselves, have been suggested for preparation of nanocomposites with SNC up to now. 2-5 Among those reported SNC filled polymer nanosystems, the biodegradable aliphatic polymer-based ones are very attractive because both the matrix and filler particles are biodegradable or bio-originated. It means that this kind of nanocomposites are fully green. The reported work revealed that the presence of SNC had good reinforcement to the aliphatic polymers, such as polylactide (PLA), 6 poly(butylene succinate) (PBS) 7

and poly(β-hydroxyoctanoate) (PHB), 8 especially to poly(ε-caprolactone) (PCL) 9-11

because PCL is of low-modulus.

12

An evident increase of tensile modulus of PCL

was reported by Habibi and Dufresne 10 in the presence of PCL-grafted SNC particles, and the composites almost had the same levels of strength and elongation with those

3



of the neat PCL. In our previous work,

11

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we found that the presence of very small

amount of acetylated SNC particles (1 wt%) had significant reinforcement and barrier effect to PCL membrane, reducing oxygen transmission rate by 70% and increasing tearing strength by about 68%. Those reported work suggested that incorporation with SNC particles might be an effective way of optimizing final performance of PCL. However, PCL is semicrystalline, which means that its final properties are not only dependent of the filled nanoparticles, but also of its crystallization histories.

12

For

example, a high degree of crystallinity favors improvement of mechanical strengths and barrier properties of PCL, but is against its biodegradability and biocompatibility. 13

The reported work revealed that the presence of polysaccharide nanocrystals, for

instance, cellulose nanocrystal, had large influence on the crystallization morphology and kinetics of PCL.

14, 15

It suggests that the presence of SNC particles might affect

the formation of supermolecular structure of PCL also. To our best knowledge, there are no literature reports on this topic, which is worthy of deep study. Therefore, in this work, crystallization behavior of the PCL/SNC composite systems were studied in detail, aiming at opening a new window to control PCL crystallization using SNC particles. Three kinds of SNC particles, including the pristine one and the acetylated ones with low-level and middle-level surface modification, were used as the filler. The different nucleation roles of those SNC particles during crystallization of PCL were detected, then. The particle-polymer compatibility in those three systems was further evaluated, with the objective to make a deep insight into the relations between nucleation abilities of SNC particles and their affinity to PCL. 4


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2. Experimental Section

2.1. Materials and Preparation Poly(ε-caprolactone) (CapaTM6400, with the number-average molar weight of 37,000 g mol-1) was purchased from Solvay Co. Ltd., Belgium. Industrial corn starch (A-type crystalline structure, with the average particle size of 10-20 µm) was purchased from Suchow Ouyang Chemical Technology Co. Ltd., P. R. China. The SNC suspension were prepared by the way of acid hydrolysis of starch reported by Dufresne et al.

16

Details can be found in the previous work.

11

As-obtained SNC

particles are platelet-like (A-type crystallites), with average platelet sizes of 88.3±7.6 nm, and the average thicknesses of 7.2±2.3 nm. Their transverse modulus is 4.2±0.6 GPa. A continuous route without freeze drying step, which was developed to prepare cellulose nanocrystal filled polylactide nanocomposites,

17

was used here to perform

the acetylation of SNC and following preparation of PCL/SNC suspensions. Detailed route can be found in the previous work. 11 The acid hydrolysis and the acetylation do not affect A-type crystal structure of starch. 11 The degree of substitution (DS) of SNC was determined using a method developed by Teramoto and Shibata

18

through the nuclear magnetic resonance spectroscopy

(NMR) analyses. The DSs of SNC were controlled within the moderate levels in this work because excessive acetylation amorphized polysaccharide nanocrystals severely, 19, 20

and as a result broke their rigid particle structure down.

15

Three kinds of SNC

particles, including pristine one, and acetylated ones with lower DS (0.38) and middle level DS (1.90), were prepared and used to be incorporated with PCL (the acetylated 5



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SNC particles with these two DSs had almost the same particle sizes and thickness with the pristine one, with monotonously decreased transverse modulus and surface degree of crystallinity

11

). The composites with the thickness of about 200 µm were

obtained by the casting of suspensions, followed by vacuum-drying to constant mass weight. Good dispersion of those SNC particles in PCL matrix has been detected in the previous work. Surface acetylation could further improve phase affinity between SNC particles and PCL chain, leading to increase of glass transition temperature of PCL, which was further confirmed by FT-IR and rheological tests.

11

Hereafter the

samples with pristine SNC and acetylated ones were referred as to PSNs, PSNLs and PSNMs, respectively, where s is the filler particle loading, and the subscripts, L and M, denote lower and middle-level DSs of SNC, respectively. 2.2. Characterizations 2.2.1. Differential scanning calorimetry (DSC) Thermal events for neat PCL and its composites in the heating and cooling processes were detected using the differential scanning calorimeter (Netzsch 204F1, Germany). The sample (about 5 mg) was heated from 0 oC to 80 oC, held for 5 min, then cooled to 0 oC, and again heated to 80 oC, during which the thermal enthalpies were recorded. To detect heat flow during isothermal crystallization, the sample was cooled from 80 o

C to the predetermined temperature with the rate of 60 oC min-1, held till exothermic

event was over. All tests were performed under nitrogen atmosphere. 2.2.2. Polarized light microscope (PLM) The growth of spherulites was recorded using a polarized light microscope (Leika 6


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DMLP, Germany) on a hot stage (Linkam LTM350, England). The same temperature ramp with DSC tests was employed here. The sample was heated from 0 oC to 80 oC at the rate of 10 oC min-1 and held for 5 min to eliminate residual stress and thermal histories, then cooled with the rate of 50 oC min-1 to a predetermined temperature for the following spherulite growth observation. All sheet specimens almost had the same thickness (about 0.15 µm). 2.2.3. Small-angle X-ray scattering (SAXS) The lamellar structure was detected through small-angle X-ray scattering instrument (Bruker AXS GmbH, NanoStar, Germany) with a Vantec-2000 2D detector. The tests were performed at room temperature, and the incident X-rays of CuKα radiation (1.54 o

A) were monochromated by a cross-coupled Göbel mirror. The distance between the sample and detector was calibrated using silver behenate, giving the scattering vector q range from 0.07 to 2.3 nm-1. The 1D SAXS profiles were collected by integration of 2D pattern, shown as the normalized intensity (I) versus q ( q = (4π / λ ) sin θ , where

λ is the wavelength of the X-rays and 2θ the scattering angle). The one-dimensional (1D) correlation function (K(z)) defined by Strobl and Schneider 21 can be plotted by K ( z) =

∞

1 2π

2

∫ I (q)q

2

cos( qz ) dq

(1)

0

where I(q) is the absolute scattering intensity collected from the SAXS tests, and z the direction along which the electron density is measured.

3. Results and Discussion

3.1. Nucleation ability of various SNC particles to PCL 7



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Figure 1 gives thermograms of PCL and its composite samples with 1 wt% particle loading. The obtained thermal parameter values are summarized in Table 1. It is very interesting that the crystallization temperature (Tc) of PCL decreases monotonously with increase of DS of SNC particles. The composites with higher particle loadings, 3 wt% and 5 wt%, reveal the same trend (Figure 2). This suggests that the nucleation ability of SNC depends on its surface properties and the particle-polymer interactions strongly. Similar dependence has also been reported on the cellulose nanocrystal filled PCL systems. 14, 15 The composite with pristine SNC particles (PSN1) shows higher Tc relative to the neat PCL, which indicates that the presence of pristine SNC provides additional nucleation sites, and as a result promotes nucleation of PCL from the melt. Similar heterogeneous nucleation has been widely reported on the PCL composites filled with a variety of filler particles.

23-28

However, the nucleation ability decreases

with increasing DSs of SNC, and the composite filled with the acetylated SNC with middle-level DS (PSNM1) shows the Tc even lower than that of neat PCL. This is called crystallization temperature depression,

15

and has also been observed on the

PCL composites with the functionalized carbon nanotubes cellulose nanocrystals.

14, 15, 30

29

or surface-modified

Thus, the filled acetylated SNC, in this case, becomes

antinucleation agent to PCL, instead of nucleating one. Clearly, the role of SNC particles during PCL crystallization alters with their surface properties. It is well known that the homogeneous nucleation of a semicrystalline polymer takes place as a result of random fluctuation of order in the mother phase, which requires a very higher supercooling.

31, 32

In the presence of foreign body, the heterogeneous 8


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nucleation is the prevailing mode of nucleation in phase transformations because it requires far lower supercooling. The heterogeneous nucleating agents are commonly crystalline substances and insoluble in the polymer melt, with a high-energy surface which favors occurrence of enough supercooling at the solid-liquid interface. 32, 33 The foreign body with low-energy surface are commonly ineffective nucleating agents because supercooling at the solid-liquid interface is insufficient to nucleate interfacial region before nucleation occurs in the bulk.

31

For the pristine SNC in this work, it is

clearly a good nucleating agent during PCL crystallization because its hydrophilic surface is incompatible with PCL matrix. After acetylation, the surface energy of SNC decreases, accompanied by the formation of some amorphous chain structure.

11, 15

In

this case, the phase compatibility is improved, while the nucleation ability of SNC particles may weaken because the thickened interface is against the occurrence of sufficient supercooling at the solid-liquid interface. For the particles filled polymeric composite system, the interaction energy parameter, B, can be used as a measure of phase compatibility: 34 0 Tm0 − Tmix =−

BViu 0 Tm (1 − φi )2 ∆H iu

(2)

0 where Tm0 and Tmix are the equilibrium melting points of polymer and composite,

respectively. ∆H iu /Viu is the heat of fusion of polymer per unit volume, and φi is the volume fraction of polymer. Tm0 can be determined by Hoffman-Weeks method. 35

B is a function of Flory-Huggins interaction parameter, χ12 , ( χ12 =BViu / RT

36

),

0 which can be obtained from the slope of the plots of Tm0 − Tmix versus (1 − φi ) 2 , as

shown in Figure 3. Here the literature-reported value of melt enthalpy of ideal PCL 9



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crystal ( ∆H m0 =136 J g-1 22) are used for calculation. The acetylated SNC particles with lower DS (0.38) are still incompatible with PCL because their composite (PSNL1) shows positive value of B. For the composite (PSNM1) containing the acetylated SNC particles with middle-level DS (1.90), however, it has a negative B value, indicating that the two phases can form the thermodynamically stable system at the temperature above the melting crystallization.

36-38

This compatible system can even be read as a

‘miscible’ one in the molten state. In this case, those SNC particles nearly lose their nucleation activity, and the short amorphous chains formed after acetylation on their surface even act as the role of diluent agent,

15, 39, 40

decreasing the probability of

thermal nucleation of PCL bulk. As a result, PSNM1 even has a lower Tc relative to the neat PCL. The nucleation activities of those several kinds of SNC particles can be evaluated by the Dobreva and Gutzow

41, 42

method. The nucleation activity, Na, is defined as the

decreased level of the work of three-dimensional nucleation with the addition of a foreign substrate. Na approaches zero if the foreign substrate is extremely active. For nucleation from melts near the melting temperature, Tm, the cooling rate ( φ ) is related to the degree of supercooling ∆Tp ( ∆Tp = Tm − Tc ):

log φ = A −

B =ω

B 2.3∆Tp2

(3)

σ 3Vm2

(4)

3kTm ∆S m2 n

where A is constant, and B a parameter related to molar volume of the crystallization polymer (Vm), and the entropy of melting ( ∆S m ), as well as the specific surface 10


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energy ( σ ). k is Boltzmann constant, n Kolmogorov-Avrami exponent and ω geometrical factor. The nucleation activity is a normalized item

N a = B* / B 0

(5)

where B* is the value of B when the polymer is filled and B0 when is unfilled, which can be obtained from the slope of log φ versus 1/ ∆Tp2 . The as-obtained values of Na are summarized in Figure 4. Clearly, the Na of PSN1 is only 0.83, confirming that the pristine SNC has good nucleation activity. As for the PSNM1, its Na is even higher than 1. In this case, Na may lose its physical meaning

14, 30

and it suggests that the

middle-level-acetylated SNC is not the heterogeneous nucleating agent to PCL any more, and the presence of those particles even impedes the nucleation of PCL. 3.2. Spherulite morphology and lamellar structure Actually the altered nucleation activities of those SNC particles can be indicated by the altered spherulite size of PCL indirectly, as shown in Figure 5. It is seen that the composites with pristine and low-level-acetylated SNC show decreased spherulite size as compared with the neat PCL, confirming that the presence of those two kinds of SNC particles provides additional nucleation sites.

14, 23, 43

However, PSNM1 sample

shows the spherulites with almost the same (42 oC) or even slightly higher size (45 oC) than the neat PCL sample. This indicates that the middle-level-acetylated SNC is inert or even antinucleation agent at higher crystallization temperature. The lamellar structure of PCL in those three systems can be further evaluated by Lorentz-corrected SAXS profiles shown in Figure 6. The long period of lamellae (L) and the average lamellar thickness ( Lc ) can be obtained using the one-dimensional (1-D) correlation 11



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function, 44, 45 as can be seen in Figure 6b. All samples have almost the same lamellar thickness and long period of lamellae within the error ranges. This indicates that the presence of SNC particles does not affect PCL lamellar structure evidently, despite their different nucleation activities, or even different nucleating roles. Besides, the presence of SNC particles does not have large influence on the PCL crystal structure (disclosed by the XRD patterns shown in Figure 7) because PCL only has one crystal form. 46 3.3. Spherulite growth kinetics of PCL/SNC composites However, the growth rates of PCL spherulite are strongly dependent of the roles of SNC particles, as shown in Figure 8a. As the nucleating agents, the pristine SNC and the low-level-acetylated one promote growth of spherulite. Relative to PSNL1 sample, the higher growth rate of PSN1 indicates that the pristine SNC has better nucleation activity than the low-level-acetylated one. PSNM1 sample shows a decreased growth rate as compared with the neat PCL, again confirming that middle-level-acetylated SNC particles can restrain crystallization of PCL in PSNM1 due to their antinucleation role. Further information can be revealed by Lauritzen-Hoffman-Miller equation: 47, 48

G = G0 exp[ −U * / R (Tc − T∞ )]exp[− K g / Tc ∆Tf )]

(6)

where G is the spherulitic growth rate, U* the activation energy for transportation of segments to the nucleation site, Kg the nucleation constant and f = 2Tc / (Tm0 + Tc ) . R is the gas constant, and T∞ the hypothetical temperature where viscous flow ceases. G0 is a pre-exponential factor. The Tm0 value can be obtained by the Hoffman-Weeks procedure. 35 12


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Figure 8b gives the plots of ln G + U * / R (Tc − T∞ ) as a function of 1/(Tc ∆Tf ) for all samples. The obtained Kg values are listed in Table 2. PSN1 and PSNL1 have decreased Kg values as compared with the neat PCL. This confirms a lower barrier for nucleation in the presence of pristine and low-level-acetylated SNC particles because Kg is proportional to the energy needed for the formation of nuclei with critical size: 49 Kg =

nib0σσ eTm0 ∆H m0 k

(7)

where σ and σ e are the lateral surface free energy and folding surface free one, respectively. b is the layer thickness, and k the Boltzmann constant. The Tc studied in this work is in regime II, 50-52 and ni is hence valued as 2. The calculated values of σ e are also listed in Table 2. The literature-reported ∆H m0 (136 J g-1 22) and b0 (0.438 nm 53

) values are used. PSNM1 shows an increased value of folding surface free energy

relative to the neat PCL, indicating a higher energy consumption in this sample as the PCL chain folded on the nuclei surface to form crystals. 14, 30 This is a solid evidence of antinucleation role of middle-level-acetylated SNC particles. Thus, the three kinds of SNCs, the pristine one, and the acetylated ones with lower and middle-level DSs, act as fully different roles, namely strong nucleating agent, moderate one, and even antinucleation one, during PCL crystallization. In another perspective, the role of SNC particles during crystallization of PCL can be tailored precisely by controlling their surface acetylation level. This opens a new door for the applications of SNC particles in the crystallization control of polymers.

13



4. Conclusion

Three kinds of SNC particles, including the pristine one and the acetylated ones with lower and middle-level DSs, were used as the modifier to control the crystallization of PCL. The pristine and low-level-acetylated SNC particles act as the heterogeneous nucleating agent role, increasing the crystallization temperature and spherulite growth rate of PCL. But the former is much stronger than the latter because improved phase adhesion is against nucleation activity. Therefore, the middle-level-acetylated SNC particles even play the role of antinucleation agent, impeding nucleation and followed spherulite growth of PCL. But the lamellar structure of PCL does not depend on the presence of SNC particles. This work provides an interesting and also effective idea to control crystallization of biodegradable aliphatic polyesters with SNC particles.

Acknowledgements

The authors thank the National Natural Science Foundation of China (51573156) and the Jiangsu Provincial Research Innovation Program for Graduates (SJZZ16_0259) for the financial support.

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21



Page 22 of 32

Table 1 thermal parameter values a) obtained from the cooling and the second heating DSC scans Samples

Tc (oC)

Tm1 (oC)

Tm2 (oC)

∆ Hm (J/g)

Xc (%)

PCL PSN1 PSNL1 PSNM1

28.3 31.0 30.0 26.0

56.0 56.3 56.0 55.7

57.2 57.2 57.1 57.1

67.4 64.5 65.7 66.3

49.6 47.4 48.3 48.7

a) Tc, crystallization temperature; Tm, melting temperature; ∆ Hm, melting enthalpy; Xc, degree of crystallinity ( X c = ∆H m / ∆H m0 , ∆H m0 = 136 J g −1

22

); the scan rate was 5 oC min-1.

Table 2 the calculated values of kinetic parameters of spherulite growth samples

105Kg (K2)

σe (erg/cm2)


0.83 0.67 0.72 0.85

85.78 69.55 75.12 88.98

22


Page 23 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


FIGURE CAPTIONS Figure 1 DSC traces recorded from (a) cooling and (b) the second heating scans with the rate of 5 oC min-1 for neat PCL and the composites with 1 wt% particle loadings.

Figure 2 DSC traces for the PCL composites with (a) 3 wt% and (b) 5 wt% particle loadings with the cooling rate of 5 oC min-1. 0 Figure 3 Determination of equilibrium melting points (left) and the plots of Tm0 − Tmix

against (1 − φi ) 2 (right) for the PCL composites with various particle loadings.

Figure 4 Plots of log φ against 1/ ∆Tp2 for the SNC filled PCL composites. Figure 5 PLM images of the final spherulite morphology of all samples with the scale bar of 50 µm.

Figure 6 (a) SAXS patterns and (b) one-dimensional correlation function curves for neat PCL and its composites.

Figure 7 XRD patterns for neat PCL and its composites. Figure 8 (a) spherulite growth rates (44 oC) and (b) Lauritzen-Hoffman-Miller plots for all samples.

23



Figure 1 (a)

(a)

(1) PCL (2) PSN1 (3) PSNL1

exo

(4) PSNM1

(3)

(4) (1)

(2) 20

25

30

35

40

o

45

temperature ( C)

Figure 1 (b)

Tm1

(1) PCL (2) PSN1 (3) PSNL1

(b) Tm2

(4) PSNM1

exo

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 32

(4) (3) (2) (1)

30

35

40

45

50

55

tempetature (oC)

60

24


65

70

Page 25 of 32

Figure 2 (a)

(a)

(1) PCL (2) PSN3 (3) PSNL3

exo

(4) PSNM3

(4) (3)

(1)

(2)

15

20

25

30

o

35

40

45

temperature ( C)

Figure 2 (b)

(b)

(1) PCL (2) PSN5 (3) PSNL5 (4) PSNM5

exo

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(4) (1) (3) 15

20

25

30

(2)

o

35

temperature ( C)

25


40

45


Figure 3 3

PSNL B=101.03 cal/cm

80

2

1

0

o

Tm ( C)

70

60

PSNL1

-1

PSNL3

50

PSNL5

-2

PSNL7

40

3

PSNM B=-88.74 cal/cm

80

Tm (oC)

5

4

3

PSNM1 PSNM3

50

40 30

-3

2

PSNM5 PSNM7 40

50

70

0.0

1

0.5

1.0

1.5

1000(1-φi)

o

Tc ( C)

26


2.0 2

2.5

3.0

∆Tm0 (oC)

70

60

∆Tm0 (oC)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 32

Page 27 of 32

Figure 4

1.0

PCL Na=0.83 PSN1

0.9

Na=0.89 PSNL1 Na=1.12 PSNM1

0.8

logφ

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.7 0.6 0.5 0.4 0.0008

0.0010

0.0012

0.0014 2

0.0016

-2

0.0018

1/∆Tp (K )

27


0.0020


Figure 5 42 oC

45 oC

PCL

PSN1

PSNL1

PSNM1

28


Page 28 of 32

Page 29 of 32

Figure 6 (a)

intensity (a.u.)


(a) 0.00

0.05

0.10

-1

0.15

0.20

q (Å )

Figure 6 (b)

1.2

K(Z) (mol.e/cm3)2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.6

0.0

-0.6

-1.2

Lc

L (nm) Lc (nm) PCL 12.96 5.16 PSN1 12.85 5.15 PSNL1 13.16 5.39 PSNM1 13.50 5.26

L

(b) 0

10

20

30

Z (nm)

29


40


Figure 7

110 111 200

intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 32

PSNM1 PSNL1 PSN1 PCL 10

20

30

o

40

2θ ( )

30


50

Page 31 of 32

Figure 8 (a)

normalized diameter (µm)

30

(a)

25 20 15

PCL PSN1 PSNL1

10 5

PSNM1

0 0

50

100

150

200

250

time (s)

Figure 8 (b)

-9.6

PCL PSN1 PSNL1

(b)

-9.8

lnG+U*/R(Tc-T∞)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


-10.0

PSNM1

-10.2 -10.4 -10.6 -10.8 -11.0 10.0

10.5

11.0

11.5

12.0

105(Tc∆Tf )-1

31


12.5

13.0


Table of Content


Page 32 of 32

Crystallization of Green Poly(Îµ-caprolactone) Nanocomposites with

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