Melt Mixing Method Research Articles

Assessment of localization and degradation of ZnO nano-particles in the PLA/PCL biocompatible blend through a comprehensive rheological characterization

The aim of this work was to investigate the effect of addition of various amounts of zinc oxide (ZnO) nanoparticles on the polylactide/polycaprolactone (PLA/PCL) blend prepared by melt mixing method. The morphological, rheological and degradation of prepared nanocomposites were studied. The morphology was characterized as dispersed PCL droplets into the PLA matrix, and according to Young's equation, zinc oxide nanoparticles (ZnO-NPs) was anticipated to preferentially locate in the matrix phase. The results of ATR-FTIR and the hydrolytic degradation tests demonstrated that, addition of ZnO-NPs introduced an accelerated degradation on the PLA/PCL blends. Subsequently, comprehensive linear viscoelastic evaluations were carried out to support these results and also give a deeper insight on the possible influences associated with the ZnO-NPs incorporation. Rheological results showed that with increasing nanoparticles, the elastic modulus and the complex viscosity decreased, which it was correlated to the degradation and chain scission of polymeric chains induced by ZnO-NPs.

Synergistic influence of keratin and TPU: An approach towards bioinspired artificial skin

Abstract Inspired from the keratin-elastin composition of the human skin, here we have developed a robust, flexible and biocompatible composite film of thermoplastic polyurethane (TPU) and bio-waste human hair keratin using extrusion-based melt-mixing method for artificial skin applications. During the melt-mixing, the molecules of TPU and keratin forms H-bonding among their polar functionalities. The H-bonding interaction between TPU and keratin molecules was studied and verified by FTIR and 1H NMR results. Because of both the H-bonding interaction (between TPU and keratin) and lubricating behavior of cysteine-rich keratin, TPK exhibits unique mechanical and tribological performances. Hygroscopic keratin enhances the hydrophilicity and the porous morphology allows the moisture permeability of TPK. TPK containing 1 wt% keratin (i.e., 1% TPK) shows elastic modulus of 31.44 MPa, ultimate tensile strength (UTS) of 18.52 MPa, coefficient of friction (COF) of 0.18 and water contact angle of 85° which are closer to that of the human skin of different body parts. Also, the 1% TPK shows very high toughness value of 77.5 J*m−3*106, which is similar to that of the mammalian collagen fibrils.

Preparation and Characterization of Composite Blends Based on Polylactic Acid/Polycaprolactone and Silk

Silk-reinforced polylactic acid/poly ε-caprolactone composites containing 1-7 wt % of silk fibers were fabricated through the melt-mixing method. The composites were then characterized by implementing Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and rheometry to investigate functional groups, thermal properties, rheological properties, and intrinsic viscosities of each composite. The crystallinity of the composites was found to decrease upon addition of silk, while, both storage modulus ( G') and loss modulus ( G″) were increased which is an indication of interface bonding between the polymer and silk. The composite containing 5% silk fiber (PLACLS5) showed the optimum results. The composites' morphological analysis was conducted by scanning electron micrograph coupled with energy dispersive X-ray (SEM-EDX) mapping to assess the fiber dispersion in the composite matrix. The contact angle measurements and in vitro degradation were performed to evaluate the hydrophilicity, free surface energy, and hydrolytic degradation of the composites. The results implied that addition of higher contents of silk fiber could reduce the degradation duration of the composites, which is due to the high hydrophilicity of the fiber, uniform fiber dispersion within the matrix, the porous structure, and consequently, the hydrophilic behavior of the composites. These composites can be great alternatives for both soft and hard tissue engineering applications.

Effect of MWCNTs on Wetting and Thermal Properties of an Immiscible Polymer Blend

Poly (trimethylene terephthalate)/Polypropylene blend (PTT/PP) is prepared using melt mixing method and 1 wt% multiwalled carbon nanotubes (MWCNTs) are incorporated to study its effect on the thermal and wetting properties. The droplet morphology reveals the immiscibility of the neat polymers in the blend and there is a reduction in the domain size of the dispersed phase with the addition of MWCNTs due to the compatibilization effect of MWCNTs. With the addition of MWCNTs, there is a slight improvement in the melting temperatures of both PTT and PP while an increase in the crystallization temperature and glass transition temperature (Tg) is observed that may be due to the nucleation effect of MWCNTs. On blending with PP, the thermal stability of PTT matrix is increased and with the addition of MWCNTs there is not much improvement in the thermal stability of the polymer components is observed. With the addition of MWCNTs the contact angle of the blend slightly increased, may be attributed to the hydrophobic nature of MWCNTs.

Structure and thermal properties of expanded graphite/paraffin composite phase change material

ABSTRACTDifferent contents of expanded graphite (EG) composite phase change material (PCM) were prepared by the melt mixing method, taking paraffin as the PCM and EG as the supporting material. Phase compositions of EG, paraffin, and EG/paraffin composite were investigated using X-ray diffraction (XRD). Microstructures of EG and EG/paraffin composite PCMs with different EG contents were observed by a scanning electron microscope (SEM). Thermal properties, such as phase-transition temperature and latent heat of the materials, were determined by differential scanning calorimetry (DSC). Mass loss and thermal properties after 100 heating cycles were measured. The results show that physical absorption exists between paraffin and EG. EG is beneficial for the PCM composite to reduce leakage of paraffin, decrease the phase change temperature and latent heat, and strengthen the thermal stability. The solid–liquid phase change latent heat of materials is larger than that of the solid–solid one. The heating cycle has little effect on the phase-transition temperature and latent heat.

PROPERTIES OF COMPOSITE BASED ON HIGH DENSITY POLYETHYLENE/ETHYLENE VINYL ACETATE BLEND AND A NOVEL ORGANIC MODIFIED WASTE GYPSUM

In this study, waste gypsum (WGS) was used as the filler in blend of high density polyethylene (HDPE) and ethylene vinyl acetate copolymer (EVA) in order to improve the flame resistance of this composite. After modification by ethylene bis stearamide (EBS), modified gypsum (EGS) at various contents was dispersed into HDPE/EVA blend by melt-mixing method to obtain EGS/HDPE/EVA composites. The IR analysis of the EGS showed the interaction between EBS and gypsum. The difference in morphology of HDPE/EVA/EGS and HDPE/EVA/OGS composites was also observed in SEM images. By adding EGS and small amounts of flame retardant additives such as ammonia polyphosphate and zinc borate, the thermal stability and the flame resistance of HDPE/EVA/EGS composites have improved and classified at V2 grade of UL94 standard. Moreover, the second self extinguishing time (t2) of EGS composite is shorter than that of unmodified gypsum (OGS) composite because of the quality char forming after the fist burning and it plays a role as thermal barriers to protect material from heat of the second ignition. About mechanical properties, both tensile strength and elongation at break of the composite decreased with increasing the gypsum content and flame retardant additives because of filler aggregation.

Graphene oxide modification for enhancing high-density polyethylene properties: a comparison between solvent reaction and melt mixing

Abstract Graphene oxide (GO) was chemically modified in xylene with dodecyl amine and hydrazine monohydrate to obtain reduced functionalized graphene oxide (RFGO). Composites of high-density polyethylene (HDPE) and GO were made via solvent reaction, whereas both melt mixing and solvent reaction were used for HDPE-RFGO composites for comparison purposes. Elemental and thermal analysis showed the success of GO modification in grafting amine functionalities onto its structure and restoring most of the original graphene C=C bonds. A significant increase in mechanical properties, thermal stability, and crystallization behavior was observed for HDPE-RFGO (solvent) compared with HDPE and HDPE-GO, proving that homogeneous dispersion of RFGO in the polymer matrix and strong interactions between them resulted in facilitated stress transfer, delayed thermal degradation, and more efficient nucleating effect in inducing the crystal growth of HDPE. A comparison of HDPE-RFGO properties enhancement between the melt mixing method and the solvent reaction method showed that, apart from mechanical behavior, the RFGO contribution was the same, suggesting that the optimization of the ecofriendlier approach (melt) could eventually lead to its total use for the mass production of high-performance, cost-effective, and more environmentally friendly graphene-based thermoplastic polyolefin nanocomposites suitable for highly demanding industrial applications.

Preparation of pharmaceutical cocrystal formulations via melt mixing technique: A thermodynamic perspective

The aim of the present study was to evaluate the thermodynamic properties of in-situ formation of cocrystal formulations by the melt-mixing method. Specifically, the thermodynamic mixing behaviour of carbamazepine-nicotinamide and ibuprofen-nicotinamide cocrystals prepared with the aid of Soluplus® (SOL) were evaluated using thermodynamic lattice-based solution theories. Thermodynamic miscibility of both cocrystals with SOL was predicted by calculating Gibb′s free energy based on the Flory-Huggins (FH) interaction parameter (χ), while the activity coefficient of cocrystals estimated with the aid of solid–liquid equilibrium equation and FH lattice theory, showed good thermodynamic miscibility of the components at elevated temperatures used normally during melt-mixing based processes. Complete phase transition diagrams constructed with the aid of DSC measurements and FH solution theory, suggested the existence of two transition zones: (1) a stable cocrystal zone, located at the right-hand-side of the spinodal phase separation curve, where stable cocrystals are prepared and (2) an unstable cocrystal zone, located at the left-hand-side of the spinodal curve up to liquidus, where the matrixforming polymer sets a kinetic barrier to recrystallization and hence, a barrier to the formation of cocrystals. The validity of the suggested thermodynamic phase transition zones was experimentally verified by ATR-FTIR and hot-stage polarized light microscopy.

Complex modification effect of linseed cake as an agricultural waste filler used in high density polyethylene composites

Linseed cake (LC) is a by-product of agricultural industry which does not have any large-scale industrial applications. The possibilities of its utilization as filler with plasticizing ability for high density polyethylene (HDPE)-based composites have been investigated. Composites containing 5, 10, 20 and 30 wt% of the waste filler have been prepared using a melt mixing method. The influence of the LC on the mechanical and thermomechanical properties of the composites, as well as their water absorption and morphology, have been evaluated by the following methods: static tensile test, impact strength assessment using Dynstat method, hardness measurements, differential scanning calorimetry, dynamic mechanical thermal analysis, scanning electron microscopy observations, measurements of Vicat’s softening temperature and water uptake test. Application of different measuring techniques allows for describing complex modification effects of the composites’ properties changes induced by the presence of lignocellulosic filler with high oil content. The results of the study proved a pronounced influence of LC on high density polyethylene-based composites, especially a plasticizing effect of crude linseed oil contained by the waste filler particles. LC also has been assumed to affect the polymeric matrix crystallization process. It was found that complex modification of polyethylene results from simultaneously occurring different phenomena including: plasticization of the HDPE by linseed oil, improved crystallinity of the semicrystalline matrix, presence of the rigid lignocellulosic particles dispersed in polymer and accumulation of the oil in the interfacial regions.

Tensile, Thermal, Dielectric and Morphological Properties of Polyoxymethylene/Silica Nanocomposites.

This paper presents the tensile, thermal, dielectric and morphological properties of composites based on polyoxymethylene (POM) and nanosilica (NS) prepared by melt mixing method at 190 °C. Based on the torque readings, the processing of POM/NS composites were found to be easier in comparison to only POM. The FT-IR spectra analysis of the POM/NS nanocomposites showed the presence of peak at approximately 910 cm-1, attributed to the Si-O and C-O groups in NS and POM on the POM/NS nanocomposite. The absorption at these peaks increased on gradually increasing the content of NS. Tensile property testing (tensile strength, elongation at break, and Young's modulus) indicated that the tensile strength of POM/NS nanocomposites increases as the NS content increases from 0.5 wt.% to 1.5 wt.%, and sharply dropped when the NS content was more than 2 wt.%. A similar trend was observed for Young's modulus and elongation at break of the nanocomposites. The DSC analysis of the nanocomposites showed that the melting temperature (Tm) of POM/NC composites increased in the presence of low weight % of NS which can be attributed to the interaction between POM and NS leading to the rising crystallinity of all nanocomposites. POM/NS have a slightly higher temperature resistance as confirmed from the TGA analysis and POM/NS 1.5 wt.% had the maximum degradation temperature (Tmax) value and consequently the lowest weight loss. The dielectric constant of the nanocomposites increased from 3.26 to 3.56, while the dielectric loss tangent and volume resistivity were dropped, corresponding to the NS content from 0.5 to 2 wt.%. The SEM images of POM/NS nanocomposites demonstrated that the NS particles were dispersed relatively regularly into POM with a size in the range of 100 to 500 nm. They were dispersed more regularly into the polymer matrix at 1.5 wt.% NS. Based on the obtained results, the suitable NS content for the preparation of the POM/NS nanocomposites was found to be 1.5 wt.%.

Preparation and Characterization of Ni0.5Zn0.5Fe2O4 + Polyurethane Nanocomposites Using Melt Mixing Method

In this study, nanocomposites of Ni0.5Zn0.5Fe2O4/polyurethane were prepared by melt mixing method and determined the influence of amount of Ni0.5Zn0.5Fe2O4 (0, 0.5, 1, 2, and 3 wt%) fillers on magnetic induction of segmented polyurethane composites with optimum processing conditions. The obtained nanocomposites particles of all the samples were characterized by TGA (Thermogravimetric Analysis), DSC (Differential Scanning Calorimetry), XRD (X-Ray Diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (Scanning electron microscopy) and Hysteresis measurements (P-E Loop tracer) & VSM (Vibrating Sample Magnetometer). XRD showed the strong characteristic diffraction peaks for ferrite while diffused diffraction pattern for polyurethane. Moreover on increasing nano fillers concentration causes the agglomeration in the composites owing to irregular distribution and consequently the strength of the material reduced. FTIR spectroscopy showed that the positions of peaks for distinctive functional groups of both ferrite and SPU. Micrographs showed that Ferrite/SPU nanocomposites having good dispersion of filler in matrix.

Investigation of gear performance of MLNGPs as an additive on polyamide 6 spur gear

ABSTRACTMolded plastic gears have long provided an alternative to metal gears in lightly loaded drives. They transmit power quietly and often without lubrication in numerous applications, furthermore decrease the quantity of parts and oppose chemicals in numerous applications. Previously, plastic gears were restricted to to 0.25 hp because of varieties in their properties and uncertainties about how they react to natural conditions such as moisture, temperature and chemical. Today, better molding controls combined with design practices that more accurately encompass environmental factors have boosted plastic gear drive capacity to 1.5 hp. Using reinforcement this is standout amongst the most practices to enhance the gear performance.This study estimated the effects of multilayer graphene nanoplatelets (MLNGPs) as an additive on polyamide 6 (PA6) spur gear performance. These include strength, elastic modulus, thermal stability, dynamic mechanical analysis, moisture absorption, and wear characteristics.The nanocomposite gear was made by melt mixing method and injection moulded into thick flanges. The flanges were machined using CNC milling machine to produce spur gear. The wear experiments were performed at a running speed of 1400 rpm and at torques of 13 and 16 Nm with different concentration 0, 0.1, 0.3 and 0.5 wt% MLNGPs using test rig. The result showed that 0.3% of MLGNPs is the optimum concentration. Young's modulus increased up to 40%, Vickers microhardness value increased up to 25%, storage modulus E’ is increased up to 37% and glass transition temperature is increased up to 14%. On the other hand TGA result shows that the Tonest increased up to 7.5% and Td increased up to 2%, and wear decreased by 35% at 16 Nm and 54% at 13 Nm.

Thermal and Rheological Properties of Poly(lactic acid)/Low-Density Polyethylene Blends and Their Supercritical CO2 Foaming Behavior

Low-density polyethylene (LDPE) was employed to improve the thermal and rheological properties as well as the supercritical CO2 foaming behavior of poly(lactic acid) (PLA) through melt mixing and batch foaming method, due to its long branched chain structure, moderate crystallization capacity and good foamability. The differential scanning calorimetry and polarized optical microscope results showed that the introduction of LDPE had a slight effect for promoting the crystallization of PLA. An important synergistic effect on the rheological properties of PLA/LDPE blends was found through rotational rheometer. With the content of LDPE, the size of spherical LDPE dispersion phase became bigger gradually, which was observed by scanning electron microscope (SEM). A very interesting cellular morphology evolution from flower-like cellular structure to complex cellular structure and then to mono-porous cell structure was found in the SEM images of the PLA/LDPE blending foams with the foaming temperature at 95 °C. The effect of blending ratio and foaming temperature on the cellular morphology and foaming parameters was investigated.

Shape memory characterization of poly(ε-caprolactone) (PCL)/polyurethane (PU) in combined torsion-tension loading with potential applications in cardiovascular stent

Shape Memory Polymers (SMPs) were proved to be employable for biomedical application but still their performance in progress. In this study, the combined torsion and tension loading of polyurethane/poly(ε-caprolactone) (PU/PCL) blend as SMP were investigated experimentally. In addition to the viscoelastic response, the stress and shape recovery are studied. Samples are characterized by DSC, DMTA and tensile test to accomplish higher performance. Results showed that samples prepared by solution mixing method has higher storage modulus and loss modulus respect to samples blended by melt mixing method. In order to extend the usage, the pre-torsion and pre-stretch strains were imposed on PU/PCL strips and stress recovery and shape recovery were reported. The results show that higher stress recovery response demands higher pre-stretched and lower deformation temperature. Maximum stress recovery occurred in deformation temperatures of 30 °C and 40 °C. Also, angle recovery behavior in low pre-torsion was dependent on pre-stretch while tension recovery was slightly affected by pre-torsion in the angle of 540° and 720°. Among all parameters, the heating rate has the greatest effect in reducing recovery finished temperature. These new findings can be used to develop new SMP structures in the combined loading condition and better performance in biomedical scaffold applications.

In situ synthesis of a microbial fouling resistant, nanofibrillar cellulose-hyperbranched epoxy composite for advanced coating applications

High performance polymeric materials have a wide variety of applications right from household smart paints and coatings to biomedical devices. This study reports a novel in situ synthesis of a hyperbranched epoxy nanocomposite (HENC). Nanofibrillar cellulose (NFC) was modified with a branch generating moiety, triethanol amine (MNFC) and simultaneously embedded with silver nanoparticles. This MNFC was utilized as a core to synthesize HENC via an in situ approach by reacting with bisphenol A and epichlorohydrin. The chemical structure of HENC was confirmed by FTIR, 1H and 13C NMR studies, with degree of branching 0.83. The poly(amido amine) cured HENC thermosets exhibited very high tensile strength (up to 160.34 MPa), without compromising the elongation at break (25.7%). Further, excellent wood to wood substrate adhesion (∼2423 MPa) was provided by the HENC. Inherent antimicrobial activity of silver nanoparticles was conferred onto HENC, as evident from the assays against Staphylococcus aureus (minimum inhibition concentration, MIC ∼120 μg/mL) and Candida albicans (MIC ∼132 μg/mL). The HENC system thus renders a microbial fouling resistant, mechanically strong coating material with excellent adhesive power. The most fascinating part of the investigation is the synthetic protocol, which is devoid of tedious solution or melt-mixing methods to generate nanocomposite.

Enhancement of mechanical, thermal and morphological properties of compatibilized graphene reinforced dynamically vulcanized thermoplastic elastomer vulcanizates based on polyethylene and reclaimed rubber

The effect of graphene nanoplatelets (GnPs) introduction into the compatibilized multiphase polymer systems such as dynamically vulcanized thermoplastic elastomers (TPVs) based on linear low density polyethylene (LLDPE) and reclaimed rubber (RR) was explored through using the experimental and theoretical analysis. The nanocomposites were prepared by using traditional melt mixing method and characterized by various experimental measurements including transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), Dynamic mechanical thermal analysis (DMTA), tensile test and rheological measurements. The morphological investigations of prepared TPV nanocomposites show the considerable effect of GnPs on the size reduction of rubber droplets. The DSC measurements indicated the role of GnPs as an effective nucleating agent in the TPV nanocomposites. The results of TGA measurements show that the GnPs can cause a higher thermal stability in LLDPE/RR TPVs especially in the presence of a maleated polyethylene (MA-PE) as a compatibilizer. The mechanical properties exploration of TPV nanocomposites represents the considerable effect of GnPs on the increasing of Young's modulus. The analytical stiffness analysis through using Christensen-Lo model with emphasizing the effect of interphase region could precisely predict the effect of various GnPs loading on the Young's modulus. Fabrication of an industrial applicable TPV nanocomposites with enhanced mechanical, thermal and morphological properties could be achieved by using both the proper loadings of GnPs and compatibilizer.

Effect of Graphene Oxide and Graphite on Dry Sliding Wear Behavior of Polyester Composites

Graphene oxide and graphite filled polyester composites were prepared by using conventional melt-mixing methods in order to improve tribological performance of polyester. It was investigated friction stability, microhardness, friction coefficient, and specific wear rate of the composites in details. It was found that the presence of graphite and graphene oxide influenced friction coefficient and wear rate of the composites. Graphene oxide decreased wear rate with increasing of test speed and graphite decreased wear rate for composite for all speeds. Tribological performance of the polyester/graphene composites is mainly attributed to bigger thermal conductivity for graphene, which can easily dissipate the heat which appears during the friction process at bigger forces. The positive influence of graphite on coefficient of friction (COF) of the composites is the result of the clivage of graphite layers during the loadings due to van der Waals weak bonds between the graphite layers.

Insights into crystallization and melting of high density polyethylene/graphene nanocomposites studied by fast scanning calorimetry

Graphene nanoplatelets (5 wt%) with different diameters (5 and 25 × 10−6 m in diameter, 6 × 10−9 m in thickness) filled high density polyethylene nanocomposites were prepared by the melt-mixing method and the effect of graphene nanoplatelets on the polymeric matrix are then investigated by X-ray diffraction, polarized light microscopy, differential scanning calorimetry, fast scanning calorimetry, and rheology. Polarized light microscopy revealed that graphene nanoplatelets of 5 × 10−6 m promote the decrease in the size of the spherical aggregates during crystallization compared to larger nanoplatelets. From rheological measurements, it was found that even though the viscosity of the nanocomposites with increasing filler diameter was increased significantly compared to the neat polymer, the processability of these materials was not affected. Several melting events for neat high-density polyethylene and graphene nanocomposites were observed by fast scanning calorimetry associated with the small imperfect crystals grown at large supercooling, the nucleation efficiency and the diameter size of the filler. The activation energy values versus the relative extent of crystallization revealed that graphene nanoplatelets block the movement of the molecular segments and make crystallization difficult, especially at the final stage of the process. Based on this work, it can be concluded that the nanocomposite with the smaller diameter showed the most enhanced crystallization kinetics as graphene increased the number of nucleation sites, while the larger ones hindered the melted molecules in reaching full isotropization above the melting temperature.

Optical and electrical characterization of gamma irradiated low density polyethylene/paraffin wax blend

Blends of LDPE/wax in ratios of 100/0, 98/2, 96/4, 94/6, 92/8, 90/10 and 85/15 (w/w) were prepared by melt-mixing method at the temperature of 150 °C. It was found that increasing the wax content more than 15% leads to phase separation. Optical and electrical properties of pure LDPE, pure paraffin wax and LDPE/paraffin wax blends were studied before and after gamma irradiation. The optical band gap (Egopt) and Urbacht energy (Eu) in the LDPE/paraffin wax blends were determined. The results show a decrease in Egopt and increase in Eu by increasing paraffin wax ratio. The transition energy for electrons is an allowed indirect. The electrical properties including dielectric constant (ε'), dielectric loss (εʺ) and the ac conductivity (σac) in the frequency range (50 KHz–1 MHz) at room temperature were investigated. ε′, εʺ and σac increase with increasing paraffin wax ratio. ε′ and εʺ values are higher at low frequencies, while at high frequencies the trend is reversed. Influence of gamma radiation on the optical and electrical properties for the pure samples and LDPE/paraffin wax blends has been evaluated at different gamma irradiation doses (25 kGy, 50 kGy and 75 kGy). It was found that Egopt decreases, while Eu increases with increasing irradiation dose. Also, we report an increase in ε′, εʺ and σac with increasing irradiation dose. The results of the optical and electrical characteristics indicate a relation between the amorphous nature of the samples and electrical conductivity.

Effect of octa(epoxycyclohexyl) POSS on thermal, rheology property, and foaming behavior of PLA composites

ABSTRACTFoams of poly(lactic acid) (PLA)/octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (ePOSS) composite were prepared by melt‐mixing and solid‐state foaming methods. A systematic and accurate method was applied to evaluate the effects of epoxy‐based POSS on the structure of dispersion, thermal behavior, and rheological properties of PLA composites. The application of secondary electron–electron back‐scattered diffraction technique was used to observe the cellular micromorphology and micro‐phase dispersion in composite foams, simultaneously. The results indicated that secondary dispersion of POSS aggregates occurred in foaming process. The enhanced melt elasticity, dispersity of POSS, and crystallization morphology of PLA/POSS composite had a significant effect on the controlling foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA/POSS composite foam with high expansion ratio was obtained with a proper content of POSS in the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46399.