Insight into understanding the influence of blending ratio on the

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Materials and Interfaces

Insight into understanding the influence of blending ratio on the structure and property of HDPE/PS microfibril composite prepared by vibration injection molding. Yixin Jiang, Dashan Mi, Yingxiong Wang, Tao Wang, Kaizhi Shen, and jie zhang Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.8b05158 • Publication Date (Web): 25 Dec 2018 Downloaded from http://pubs.acs.org on December 26, 2018

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Industrial & Engineering Chemistry Research

Insight into understanding the influence of blending ratio on the structure and property of HDPE/PS microfibril composite prepared by vibration injection molding. Yixin Jiang, Dashan Mi, Yingxiong Wang, Tao Wang, Kaizhi Shen, Jie Zhang* College of Polymer Science and Engineering. State Key Laboratory of Polymer Materials Engineering. Sichuan University. Chengdu 610065, China The email address of corresponding author: [email protected] Abstract To achieve the goal of preparing in-situ microfibril composite (MFC), multiple strong shear flows were imposed on the melt of high density polyethylene (HDPE) /polystyrene (PS). During vibration injection molding (VIM), both phase morphology and crystalline structure show big difference from the common injection molding (CIM) samples. The PS phase would deform into ultrafine microfibrils and then absorbs the HDPE matrix to form shish-kebab super crystalline structure. The morphology analysis shows that when PS content increases, the size and morphology would change correspondingly. When PS content reaches some level, it would impair the mechanical performance. This work also analyzes the relationship between blending ratio with crystalline structure and explains the difference. These results provide a valuable insight into immiscible polymer systems under shearing field and have its industrial prospect in the future. Key words: in-situ microfibril, MFC, vibration injection molding, composite, blending ratio Introduction With the development of polymer composite industry, fiber composites have been investigated for decades and are used in many fields in our daily life, like high-strength composite1, absorption material2, biodegradable material3 etc. Among different kinds of fiber reinforced composites, one type named “microfibril reinforced composite (MFC)” has evoked researchers’ interest for its huge advantage in manufacture and great potential for functionalizing and strengthening4-7. Though MFC exhibits great advantages, there still exists one problem: the fibril is formed during drawing so the remelting step is necessary. Lately, researchers found that under some designated process technologies, such as microinjection molding8 and gas-assisted injection molding9-10 , which all can provide strong shear force during process, these special composites can

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be prepared. But these technologies only can prepare products with given size and structure, and the content of microfibrils is also limited. Recently, our lab developed a new technology called vibration injection molding (VIM), the mechanism of which has been discussed in our previous papers11-13. By using this technology, the polymer melt in the mold cavity can go through multiple shear flows during the packing stage provided by oscillatory pressure and we successfully prepared the MFC composed of HDPE and PS14. Under the strong shear flow process condition, the PS phase can exist as microfibril from the surface to the core region of the sample with an average diameter of submicron level, while the matrix also goes through shear which promotes HDPE to form some super crystalline structure like shish-kebab and hybrid shish-kebab. It is widely accepted that the performance of fiber reinforced composites depends on the characters of fiber to a large degree, such as the length (L), the length and diameter ratio (L/D) and the spatial arrangement. Many researchers have investigated the effect of fiber size on the mechanical properties of composite. When L/D ratios is low, stress would concentrate which leads to the strength decrease.15 The length of fiber also plays an important role in fiber reinforced composite. 16 The use of long fibers has been proven to increase the elastic modulus and the tensile strength of the material.17-18 Besides the inherent characteristics of fiber, the existence of fiber also affects the matrix’s properties. Based on other researchers’ investigation, the introduction of fiber would facilitate the crystallization process and affect the crystallization kinetics.19-20 During VIM, the process parameters, properties of blend system and the blending ratio determine the final fiber morphology and the properties of matrix to a large extent. Although MFC composed of HDPE/PS has been successfully prepared by VIM, how to control the fibril characteristics in this process and their influence to the final property are still unknown. When MFC is prepared during the process of VIM, the fibrillating and molding occur simultaneously. The strong shear force changes the chain orientation and some super crystalline structure like shish-kebab and hybrid shish-kebab also form in this complicated process. Shish-kebab shows great potential on impact strength, modulus, stiffness, and thermal stability, and has been studied intensively.

21

For hybrid shish-

kebab (HSK), it was first reported by Li et al when processed carbon nanotube (CNT) with polyolefin and evoked great attention of other researchers.22-24 In this structure, the polymer lamellar crystals form kebab and the filler which can be CNT and whisker forms the shish. This special crystal can dramatically enhance the interfacial interaction


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and improve the mechanical property.10,

25-26 27.

These two crystalline structures all

show high orientation degree. Besides crystalline structure and orientation degree, the size of crystal region, and the degree of crystallinity all have profound effect on the final properties of semi crystalline polymer. When the parameters of blending ratio changes, what’s the corresponding influences to these factors and the mechanical performance of different samples are worthy to investigate. In this work, we prepared MFC composed of two immiscible polymers: high density polyethylene (HDPE) and polystyrene (PS) using VIM. Based on the previous investigation, we try to find more information about this special composite and the relationship between structure and property by changing the blending ratio. Here, dynamic rheology measurement was carried out for investigating the phase behavior during shear. Scanning electron microscope (SEM), two-dimensional small angle Xray scattering (2D-SAXS) and wide-angle X-ray diffraction (WAXD) were taken to examine the phase and crystal change. All the results show that the blending ratio has a profound impact on the chain response, phase morphology, crystalline morphology and final mechanical property of composites. Experiment: Materials： High density polyethylene (trade name 5000s) was purchased from Lanzhou Petroleum Chemical Co, with a melt flow rate (MFR) of 1.18 g/10 min (190 °C, 2.16 kg). Polystyrene (trade name 5250) was purchased from Taihua Petroleum Chemical Co, with a melt flow rate (MFR) of 7 g/10 min (200℃, 5kg). Sample preparation: HDPE and PS were melted together by a SHJ-25 co-rotating twin-screw extruder. The screw speed was 120 rpm and the temperatures from hopper to die were 150,170, 180, 200, 200, 200, 200, 200 and 190°C. The pelletized and dried pellets were then molded by the home-made vibration injection molding equipment. The injection temperature was 160 to 200°C from hopper to nozzle, and the mold temperature was 50°C. In order to achieve the goal of preparing MFC, several paraments need considering in VIM process, like: melt temperature, mold temperature, vibration pressure, vibration velocity, the vibration times and the time interval between two times of vibration. For comparison, the pure HDPE sample was also molded at the same



technological parameters. Samples were labeled by the existence of PS and the preparation method. For example: VIM PS10 means containing 10wt% PS, 90wt% HDPE and made by vibration injection molding. Three kinds of samples with different blending ratio were prepared and labeled as: PS10, PS20, PS30. The size of injection molded sample is 50×80×3 mm3 as shown in figure 1 and the segments for detailed analysis were taken from the same position in each sample as described. Characterizations: Dynamic rheology measurements Rheological property was measured using a rotational rheometer (Bohlin Gemini 200; Malvern Instruments, Malvern, England). All samples were compressed into disks with a diameter of 25 mm and a thickness of 1 mm at 200℃ and 10 MPa. Measurements were carried out at 200°C, over a range of frequency from 0.01 to 100 Hz. Before the start of measurement, the specimens were kept for 5 min between the gap of the two plates in order to eliminate the thermal history. Scanning electron microscope (SEM) To carefully observe the two phases morphology along the flow direction as shown in Figure 1, the PS phase was etched away by the xylene for two hours at 20℃. In order to reveal the interior crystalline morphology, the samples were chemically etched in an acid etching solution at 55 ℃ for 6 hours. The solution consisted of sulfuric acid, phosphoric acid and distilled water. The volume fraction is 10: 4: 1. After gold sputtering treatment, etched surfaces were characterized with a FEI (Nova Nano SEM450) SEM device. Differential scanning calorimetry (DSC) A DSC (TA Q200) device was used for analyzing the thermal behavior of different samples. All measurements were carried out under dry nitrogen atmosphere. Samples about 5-10 mg were heated from 40 °C to 200 °C at a heating rate of 10 °C/min. The following equation was utilized for calculating the total crystallinity Xc of each sample: Xc =

∆𝐻𝑚 ∆H0𝑚𝛷𝑚

Where ∆𝐻𝑚 represents the measured value of the enthalpy of fusion obtained from the DSC experiment. ∆H0𝑚 means the fusion enthalpy of completely crystallized


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HDPE which was selected as 293 J/g in this paper. 𝛷𝑚 means the mass fraction of HDPE in composites. Mechanical test The standard dumbbell bars were made for tensile strength test performed by an Instron testing machine (model 5967) with the across head speed of 50 mm/min at room temperature. The values of the mechanical property were calculated as an average of over five samples. X-ray Measurements The synchrotron X-ray experiment was carried out on the BL16B1 beamline in the Shanghai Synchrotron Radiation Facility (SSRF), Shanghai, China. The dimension of the rectangle-shaped beam was 0.5 × 0.8 mm2, and the wavelength of light was 0.124 nm. The sample-to-detector distance was 207 and 1780 mm for WAXD and SAXS, respectively. A MAR CCD X-ray detector (MARUSA) was employed for detection of 2D-SAXS images, having a resolution of 2048 × 2048 pixels. The rectangular beam was perpendicular to the plane as Figure 1 illustrates and was moved from the surface to center region with the interval distance about 0.3 - 0.4mm and irradiated at 5 positions. The distance was estimated about 200μm, 500μm, 800μm, 1200μm, 1500μm away from the surface, respectively.

Figure 1. Schematic diagram of sample prepared for analyzes. FD, flow direction; TD, transverse direction; ND, normal direction. Herman's method is employed to evaluate the orientation of crystals, which is



defined as: 3𝑐𝑜𝑠∅2 ― 1 f= 2 In this equation, cos∅2 is the orientation factor defined as: 𝜋/2

𝑐𝑜𝑠∅2 =

∫0 𝐼(∅)𝑐𝑜𝑠∅2𝑠𝑖𝑛∅𝑑∅ 𝜋/2

∫0 𝐼(∅)𝑠𝑖𝑛∅𝑑∅ Where ∅ is the angle between the molecular chain direction and the melt flow direction; 𝐼(∅) is the scattering intensity at angle ∅. When the c axes of all crystals are perfectly parallel or perpendicular to the flow direction, the value of orientation parameter f is 1.0 or -0.5. And a value of 0 means the orientation being completely random. The long period (Lp) of SAXS results can be calculated by the Bragg’s law as follow: Lp =

2π q𝑚𝑎𝑥

𝑞𝑚𝑎𝑥 is the peak position of 1D-SAXS intensity profile. The crystallite thickness (Lc) is calculated as long period multiplies the crystallinity. The long period of amorphous phase (La) is calculated by Lp subtract Lc. Results and discussion

Figure 2. Complex viscosity (Pas) and viscosity ratio for HDPE, PS obtained in dynamic frequency sweep. Form Figure 2, we can see the rheological parameters of neat HDPE and PS, which


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show the typical pseudo-plastic fluid behavior. The viscosity of HDPE is higher than PS in the whole range of experimental frequency. It has been widely accepted that the low viscosity ratio (dispersed phase/matrix phase) facilitates the dispersed phase to deform, fibrillate and disperse uniformly.28-29 Some researchers pointed out that when the viscosity ratio is lower than 0.7, the dispersed phase has the ability to deform and exists as fiber after shear. Here, the viscosity ratio of PS/HDPE keeps a range from 0.2 to 0.5, which indicates the possibility for forming larger content of in-situ microfibrils in this blend system.

Figure 3. Elastic modulus (G’) for HDPE, PS and blend obtained in dynamic frequency sweep. (a) the strain is 1%; (b) the strain is 5%. Figure 3 (a) and 3(b) show that the curve of elastic modulus (G’) changes with frequency. The difference between (a) and (b) is the strain value, which are 1% and 5% respectively. The tendency of curves in two figures is similar but the value of G’ for Figure 3(a) is larger than 3(b) especially in the low frequency region. It is because higher strain means stronger shear effect that the shear thinning phenomenon would be more profound. For Figure 3(a), the values of G’ for blends and pure HDPE are close, but smaller than PS at the low frequency region. Compared with Figure 3(a), the data in Figure 3(b) exhibits another phenomenon. The G’ of blending samples is even higher than the pure HDPE and PS at the low frequency region. This behavior is known as “size-relaxation” which should be attributed to the change in shape of the dispersed phase. 30-31 Most minor phase in immiscible blending system exhibits stable spherical morphology to minimize the surface energy and keeps the thermodynamic balance. But when adding strong shear force, the sphere would deform into microfibril, which is a high-energy state on the thermodynamic aspect. The increased interfacial energy means



the relaxation trend that makes contribution to the G’. 32At the high frequency region, this energy portion is negligible compared with the elastic energy portion required for the deformation within the polymer components. This phenomenon can be observed in all the blends so when the content of PS increases, the dispersed phase still has the ability to deform and fibrillate under strong shear condition. Morphology： The morphologies for VIM PS10/PS20/PS30 are exhibited in Figure 4, which are taken along the FD. And the corresponding statistic results of fibril diameter are also given in Figure 5. For the samples VIM PS10 and VIM PS20, the fibrils arrange regularly along the FD. Fully extended, compact nanofibrils which are embedded in the matrix are clearly observed, showing an extremely high aspect ratio and orientation degree along the injection direction. When PS content is 10 and 20wt%, the particles deform, then develop into fibrils because of the shearing and arrange regularly.33 The diameter of the fibrils in Figure 5 (a) (b) (c) and (d) concentrates at 0.4-1μm. When the PS content increases to 30wt%, the particles trend to coalesce and agglomerate which leads to the average diameter rapidly increasing. Hence it would be hard for the fibrils to maintain uniform and high length-diameter ratio morphology. The diameter of fibrils in Figure 5 (e) and (f) concentrates at 0.8-1.8μm. These samples were prepared at the same processing parameters so the morphology difference can be attributed to the blending ratio.


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Figure 4. The fracture surface along the flow direction of VIM PS10: (a), (b); VIM PS20: (c), (d); VIM PS30: (e), (f). The distance from surface is 400μm for (a), (c), (e) 1500μm for (b), (d)and (f).

Figure 5. Statistics results about PS phase diameter of Figure 4. (a)-(f) corresponds to the sign in Figure 4.



Discussion The mechanical properties of the blending For blending composites, the final mechanical properties are strongly determined by the microstructure formed during processing. The morphology of HDPE/PS common injection sample shows a classic “sea-island” structure because they are thermodynamically immiscible polymers and have a poor compatibility. As is widely accepted, the interfacial interaction has a deep influence to the phase morphology and final properties. For MFC, improved compatibility is one of its advantages, as many researchers’ works have proven. 34 Therefore, when the blending ratio changes, what is the corresponding influence to the compatibility and can MFC still shows advantage are worth exploring. The tensile strength and impact strength of different samples are plotted as a function of blending ratio in Figure 6. For pure PS, the tensile strength is about 41MPa and the impact strength is about 1.8 KJ/ M2. For tensile strength of CIM samples, when PS is added, there is a slight increase but the variation is limited. The tensile strength of VIM samples increases significantly. The maximum tensile strength appears at VIM PS20 for 40MPa and keeps constant at PS30, increased by 160% compared with the corresponding CIM sample. The impact strength exhibits a different trend. Although VIM sample still has an advantage over the CIM one with the same blending ratio, the impact strength of samples with increased PS content decreases dramatically than low content one. It should be mentioned that HDPE has ideal toughness and high impact strength (29.8KJ/M2), so the improvement of tensile strength would be more useful.

Figure 6. The mechanical properties of different samples: (a) the tensile strength; (b) the impact strength.


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Figure 7 is the fracture surface of different MFC with different blending ratio. The surface is rough and uneven in Figure 7 (a) and no obvious cracks can be observed, representing severe plastic deformation behavior. When the PS content increases, the surface becomes smooth and flat. In Figure 7 (c), there are two cracks running through the sample and dividing the sample into several parts. This layered phenomenon can always be found in incompatible polymer blending system.

Figure 7. full view of fracture surface for different MFC samples with different blending ratio: (a) VIM PS10; (b) VIM PS20; (c) VIM PS30. (a’), (b’), (c’) are the magnified fracture surface of (a), (b), (c). In order to get more phase morphology information, the magnified impact fracture surface is also presented in Figure 7. The variation of different samples is distinct. In Figure 7(a’), HDPE matrix exhibits large plastic deformation which can absorb significant fracture energy.35 The deformed HDPE shields the PS fibril, causing some sub-micrometer voids and the PS fibrils are not observable in this figure. When the PS content increases to 20%wt, as shown in Figure 7(b’), some broken fibrils can be observed on the fracture surface and the plastic deformation of HDPE weakens. In Figure (c’), the PS content further increases, which results in the morphology changing correspondingly. Some PS fibrils are pulled out from the matrix that is common in commercial fiber-polymer composites and the matrix shows limited deformation. From the above SEM observation, the morphology changes dramatically when the blending ratio changes. The mechanical properties also show different tendency. The tensile strength increases with PS content and keeps constant when it reaches 20wt%, but the impact strength decreases sharply when PS content increases. The reason for



this phenomenon can be divided into two parts: the strengthening effect of PS fibrils and the damaging effect of incompatible interface. PS acts a strengthening phase in this experiment, so when the content increases, the strengthening effect would be more evident, theoretically. HDPE and PS are classic incompatible polymer system, when the minor content increases, the immiscible tendency would be greater which causes the particles to aggregate. Then the specific surface area decreasing. Finally, the stress transfer effect between dispersed particles and polymer matrix becomes poor. In the tensile strength test, the test direction is along the fibrils and oriented HDPE molecular chains direction. So, when the PS content increases, more fibrils bear the load and contribute to the strength. But when the content reaches a certain extent, the negative factors as we discussed would play the important role and damage the further improvement. From the careful morphology examination, the PS fibrils are pulled out from the surface and the matrix shows little deformation for VIM PS30. It confirms that the adhesion between HDPE and fibrils is poor and explains why the impacted strength of VIM PS30 is at a low level. The crystalline structure of MFC

Figure 8. The crystalline structure for (a)VIM PS10, (b)VIM PS20. The distance from the surface of samples is 400 µm. As we discussed before, the phase morphology of MFC changes significantly when the PS content changes. In order to get more detail information about MFC, the amorphous region was etched away by the mixing acid solution and the crystalline structure of VIM PS10, PS20 are shown in figure 8. In the VIM HDPE/PS samples, highly oriented structure can be observed at a depth of about 600μm to the outermost surface. When the distance turns to 800μm, the oriented crystalline structure is replaced


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by the random lamellae which maintains till the center region (1500μm).14 The shishkebab structure and hybrid shish-kebab structure can be found in two images of Figure 8. Compared (a) with (b), the oriented structure shows some differences. It can be seen that the kebab structure in VIM PS20 is shorter and arranges more tightly than VIM PS10. When PS content increases, it would impede the movement of HDPE chain segments because PS has stiffer structure. Then during cooling, the segments arrange into crystalline region regularly. For VIM PS20, the inhibition would make its crystal more different to growth, compared with VIM PS10. So, the matrix would trend to form shorter and dense kebab.

Figure 9. Selected 2D-WAXD patterns of VIM samples of (a)CIM HDPE; (b)VIM PS10; (c)VIM PS20; (d)VIM PS30 from the surface of samples to the core region. Figure 9 gives the selected 2D-WAXD patterns of different samples at different positions. The diffraction pattern consists of two diffraction rings associating with different lattice planes of HDPE, including (110) and (200). The diffraction patterns for CIM HDPE shows typical diffraction ring. During CIM, the shear effect is limited, so the oriented structure is also limited. The diffraction shows isotropic arc-like reflections at most positions. However, for all VIM samples, the diffraction patterns can be observed in the surface region, indicating highly oriented crystals along the flow direction. But there are some differences among them. For VIM PS10 and PS20, the



reflection is sharper and maintains on a large region in the samples. While in VIM PS30, the patterns show more isotropic diffraction rings, suggesting more isotropic structure. The calculated orientation degree in different layers is summarized in Figure 10 and the trend is more evident. The orientation degree for CIM sample stays around 0.3 which is lower than VIM samples. The orientation degree of three blending samples all increases initially and then decreases with the distance away from surface. The effect of adding PS content can be divided into two parts. On one hand, PS has stiff structure that would magnify the shear effect at the interface, 36 and on the other hand, PS would take some movement space of HDPE molecule so the orientation structure is hard to relax during cooling. For VIM PS10, maximum value of orientation degree reaches 0.8 and the minimum value is about 0.4, showing distinct difference with others. When the PS content increases, the orientation degree drops sharply. The disparity between VIM PS30 and CIM HDPE is not obvious. This difference is because PS has stiffer molecular structure, which severely restricts the molecular motion. When the PS content reaches 30%, the phase diameter increases and large numbers of stiff molecules would affect the orientation process of HDPE. So that would be difficult to form oriented structure even under the same processing parameters for high PS content sample. That’s why the PS30 doesn’t show advantage at orientation degree compared with pure HDPE.

Figure 10. The orientation degree from surface to core of different samples. For the sake of finding more information of MFC, more experiments were carried out. The DSC results are shown in Table 1. When PS is added into the matrix, the crystallinity increases with the PS content, from 0.55 to 0.59. Higher crystallinity


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represents more crystalline structure, which means PS microfibril can act as the heterogeneous nucleating agents. The melting points for all the samples don’t show big difference (Table 1). SAXS was conducted for these samples and Figure 11(a) gives the 1D integrated profiles. The peak position of blend samples trends to lower value compared to HDPE. According to Lp = 2π/q𝑚𝑎𝑥 , the Lp tends to increase for blend samples.

Sample

CIM HDPE

VIM PS10

VIM PS20

VIM PS30

Melting point (℃)

132.6

131.8

131.7

132.1

crystallinity

0.55

0.55

0.57

0.59

Table 1. The melting temperature and crystallinity of different samples.

Figure 11. (a) The corresponding intensity profiles of 1D-SAXS for different samples as a function of the scattering vector (q); (b) the plots of the extracted values of long period, crystalline thickness, amorphous size of different samples. Sample

CIM HDPE

VIM PS10

VIM PS20

VIM PS30

q (nm ―1)

0.285

0.271

0.269

0.276

Lp (nm)

22.03

23.17

23.35

22.75

Lc (nm)

12.11

13.21

13.78

13.42

La (nm)

9.92

9.96

9.57

9.33

Table 2. The value of q, long period, crystalline size, amorphous size of different



samples. Combined the DSC and SAXS results, the long period (Lp) which represents the average crystalline and amorphous repeat distance, the crystallite thickness (Lc) and the amorphous size (La) were calculated. Figure 11 (b) shows the plots of the extracted values of different samples and Table 2 gives the specific value. From the results presented here, it is apparent that on the addition of PS, the resulting crystalline morphology, orientation, crystallization kinetics and crystallinity of the homopolymer are significantly changed. 37The Lp and Lc increase initially along with the PS content increase and then have a little decline at PS30. Amorphous size doesn’t change lot but exhibits a small decline trend when PS content increase. The Lc increases because PS has the ability to act as heterogeneous nucleation point for HDPE crystallization, initially. Then, during VIM, PS phase deforms into microfibril which has a sub-micron level diameter. The chains of HDPE near the fibrils are absorbed by the small size fibrils to form the hybrid shish-kebab structure. So the perfection of crystalline structure would improve. The La decreases because more chains trend to fold and arrange into crystalline region. When the PS content increases from 10wt% to 20%, these observations of Lp and Lc become more evident. The Lp and Lc all reach the largest values for 23.35 nm and 13.78 nm. As we discussed before, the high content of PS would trend to develop into large size particles that would impair the movement ability of matrix, so the molecules of matrix have little chance to relax to an ideal position. The smallest Lc decides PS30 has the smallest La. All these results correspond to the characters of PS, HDPE chain property and phase morphology difference between different samples. Conclusion: In this work, we successfully prepared the MFC of HDPE/PS with different blending ratio. The PS phase can disperse well in the HDPE matrix and maintain the fibrous structure for the three selected kinds of samples. With the increasement of PS content, the particles would trend to coalesce and agglomerate which leads to the average diameter of fibrils rapidly grows. Due to the incompatibility, the PS30 shows the property of brittle and fragile compared to others. From the analysis about crystalline structure, when the PS content increases, the orientation degree, crystallite size would drop accordingly. All these results show the connection with the chain


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property of different polymers and blending rules. This work provides some detail information about in-situ MFC which would help to understand better and control incompatible blending system under shearing conditions better. Acknowledgements This work was financially supported by The National Natural Science Foundation of China (0030905401227). The authors would like to express sincere thanks to the Shanghai Synchrotron Radiation Facility (SSRF, Shanghai, China) for kind help on WAXD and SAXS measurements. References: (1). Priyanka, P.; Dixit, A.; Mali, H. S., High-Strength Hybrid Textile Composites with Carbon, Kevlar, and E-Glass Fibers for Impact-Resistant Structures. A Review. Mech. Compos. Mater. 2017, 53 (5), 685-704. (2). Yayun Wang, X. L., Meng Lian, Guoqiang Zheng, Kun Dai, Zhanhu Guo, Chuntai Liu b, Changyu Shen Continuous fabrication of polymer microfiber bundles with interconnected microchannels for oil water separation. Mater. Today 2017, 9 (77-81). (3). Terzopoulou, Z. N.; Papageorgiou, G. Z.; Papadopoulou, E.; Athanassiadou, E.; Reinders, M.; Bikiaris, D. N., Development and study of fully biodegradable composite materials based on poly(butylene succinate) and hemp fibers or hemp shives. Polym. Compos. 2016, 37 (2), 407-421. (4). Evstatiev, M.; Fakirov, S.; Bechtold, G.; Friedrich, K., Structure-property relationships of injection- and compression-molded microfibrillar-reinforced PET/PA6 composites. Adv. Polym. Tech. 2000, 19 (4), 249-259. (5). Evstatiev, M.; Fakirov, S.; Friedrich, K., Manufacturing and Characterization of Microfibrillar Reinforced Composites from Polymer Blends. Polym Composite: 2005; p 149. (6). ZM Li, M. Y., R Huang, W Yang, JM Feng, Poly(ethylene terephthalate) /polyethylene composite based on in-situ microfiber formation. Polym-Plast Technol 2002, 41 (1), 19-32. (7). Fakirov, S.; Evstatiev, M., Microfibrillar reinforced composites-new materials from polymer blends. Adv. Mater. 2010, 6 (5), 395-398. (8). Ding, W.; Chen, Y.; Liu, Z.; Yang, S., In situ nano-fibrillation of microinjection molded poly(lactic acid)/poly(ε-caprolactone) blends and comparison with conventional injection molding. RSC Advances 2015, 5 (113), 92905-92917. (9). Xia, X.-C.; Yang, W.; Zhang, Q.-P.; Wang, L.; He, S.; Yang, M.-B., Large scale formation of various highly oriented structures in polyethylene/polycarbonate microfibril blends subjected to secondary melt flow. Polymer 2014, 55 (24), 6399-6408. (10). Xie, D.-D.; Xia, X.-C.; Huang, Y.-H.; Chen, R.; Xie, B.-H.; Yang, M.-B., The massive formation of hybrid shish-kebab structures in HDPE/PA6 microfibril blend subjected to melt second flow. J. Appl. Polym. Sci. 2017, 134 (36), 45274.



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Insight into understanding the influence of blending ratio on the

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