Enhanced Storage Modulus Research Articles

Characterization of carbon fiber-reinforced thermoplastic and thermosetting polyimide matrix composites manufactured by using various synthesized PI precursor resins

Currently, it is important to manufacture thermoplastic advanced composites with high mechanical and thermal properties because of their higher impact resistance than thermoset composites. In this study, carbon fiber (CF)-reinforced thermoplastic and thermosetting polyimide (PI) matrix composites were manufactured by vacuum bagging followed by compression molding . Before the manufacturing process, prepregs were also prepared with various PI precursor resins by using two-step impregnation. These precursors were synthesized as poly (amic acid) (PAA), polyester amine salts (PEAS) and poly (amic acid) ammonium salts (PAAS). The PAAS precursor resin was applied as a novel method for manufacturing CF-reinforced PI matrix advanced composites. The advanced thermoplastic composite obtained from the PAAS precursor (PAAS-T) exhibited superior mechanical properties and enhanced thermal properties (near the thermal properties of thermoset advanced composites) in comparison to the other advanced composites in this study and those in the literature. However, the NA-terminated PAAS precursor (thermosetting PI precursor) did not exhibit a similar effect in terms of mechanical properties. On the other hand, the thermosetting composites exhibited highly enhanced storage modulus values up to 400 °C and outstanding thermal stability at TGA . The thermosetting composite that was obtained from the NA-terminated PAA precursor resin exhibited high mechanical properties besides its thermal properties.

Evaluation of mechanical, morphological, and biodegradation properties of natural fiber reinforced nano‐biocomposites

AbstractNanoclay modified bio resin‐based jute composites were prepared by thermopressing method to examine the effect of nanoclay on physical, mechanical, and biodegradation properties of jute‐soy composite. Fourier transform infrared spectroscopy of composite was carried out to study the chemical interactions between jute‐soy‐nanoclay, whereas, x‐ray diffractogram and transmission electron microscopic analysis revealed the formation of nanostructure at the composite interface. With 5 wt.% of clay contents, the tensile strength of the composite was 59.2 MPa, which is 65.4% higher than that of the clay‐free jute‐soy composite. The developed composite is thermally stable up to 280°C and increased in weight by only 41.66% after 24‐h water immersion. Inclusion of 5 wt.% nanoclay enhanced storage modulus of nanocomposite from 1170 to 4136 MPa. Evaluation of degradability of composites under compost condition in terms of weight and tensile loss indicated that clay reinforced composites are more durable than jute‐soy composite. Overall, a biodegradable composite material was developed which may be applied as nondegradable plastic alternate in packaging, railway coach, decorating materials, furniture, transport, and construction sector.

Mechanical Characterization of Stacked Roselle Fibre Composites: Effect of Fibre Orientation

The effect of fibre orientation on the tensile and dynamic mechanical performance of stacked Roselle fibre epoxy composites has been investigated. The hand layup method is employed to produce 0/90, 0/45 and ± 45 oriented Roselle fibre epoxy composites. The tensile test and dynamic mechanical analysis (DMA) were conducted as per ASTM standards. Results revealed that the tensile strength of 0/45 oriented Roselle fibre composite is 341% more than neat epoxy, 44% higher than 0/90 oriented composite and 106% greater than ± 45 oriented composite. As compared to pure resin, composites possess enhanced storage modulus. The composite with 0/45 orientation has higher storage modulus value than other composites. All Roselle fibre composites have up to 15% reduced glass transition temperature as compared to neat epoxy. SEM images cover the fibre pull-out and the presence of micro-voids in the epoxy matrix.

Impact of silanized milled graphite nanoparticles on thermo-mechanical properties of epoxy nanocomposite

In the recent past, graphene oxide (GO) or reduced graphene oxides (RGO) as reinforcements showed great potential to improve strength, toughness, thermal stability, and electrical/thermal conductivities of the epoxy composites. The unique structural and physical characteristics of GO or RGO make them better reinforcements for epoxies compared to other carbon-based reinforcements. However, the preparation of GO and RGO is challenging due to the requirement of strong oxidizing agents, prolonged reaction time (∼96 h), complicated and costly experimentation setup. This problem can be solved by using milled graphite nanoparticles (GrNPs). The milled GrNPs have a porous structure consisting of stacked and randomly oriented planes with a large number of defect sites. The defect sites make them easy to oxidize within a very short time of 1.5 h. In the present study, economical silanized milled GrNPs were used to improve the thermo-mechanical behavior of GrNP-epoxy nanocomposites. X-ray photoelectron spectroscopy was utilized to confirm the successful silanization of GrNPs by (3-Aminopropyal)triethoxysilane. The epoxy nanocomposite made with 0.5 wt% of silanized GrNP showed an outstanding enhancement in storage modulus of ∼758% with a considerable improvement of ∼33% and ∼43% in tensile strength and fracture toughness, respectively without sacrificing other important properties such as their thermal stability. Thus, an economical milled GrNP can be a good alternative to GO and RGO reinforcements for epoxy resins.

Rheological, electrical, and dynamic thermomechanical properties: Comparison between multiwall and double-wall carbon nanotubes in polylactide and polyamide 11

In this study, multiwall carbon nanotubes (MWCNTs) and double-wall carbon nanotubes (DWCNTs) have been dispersed in polylactide (PLA) and polyamide 11 (PA11) using an internal mixer. Rheological characterization confirmed the formation of carbon nanotube (CNT) networks in PLA and PA11 attributed to well-dispersed CNTs in the respective matrices. A lower rheological percolation threshold of PLA/MWCNT nanocomposites (less than 0.5 wt. %) compared to PA11/MWCNT nanocomposites (about 2 wt. %) confirmed the greater affinity of CNTs for PLA. The threshold for DWCNTs was below 0.5 wt. % in PLA and between 0.5 and 1 wt. % in PA11. PLA-based nanocomposites also showed higher electrical conductivity values compared to PA11-based nanocomposites. Nanocomposites containing DWCNTs exhibited higher electrical conductivities compared to those containing MWCNTs due to the higher aspect ratio of DWCNTs. Dynamic mechanical thermal analysis showed enhanced storage modulus values and reduced damping behavior with increasing content of CNTs for both polymers.

Chemical grafting fluoropolymer on cellulose nanocrystals and its rheological modification to perfluoropolyether oil

Cellulose nanocrystal (CNC) is the sustainable nanoparticle derived from natural cellulose, widely used as the functional additive to tailor the properties and performances of diverse matters. This study attempted the application of CNC as the rheological modifier in fluorocarbon lubricating oil (perfluoropolyether, PFPE). To solve the incompatibility between cellulose and base oil, fluoropolymer was covalently grafted onto the surface of nanocrystals by living radical polymerization. The introduction of modified cellulose nanocrystals exhibited significant thickening effect to PFPE-based hybrid oils, with the increase on viscosity, improved thixotropy performance and enhanced storage modulus (G′) and loss modulus (G″). In particular, when adding 10–15 wt% modified nanocrystals, a transition of G′ > G″ from the flowable state to grease-like state appeared in hybrid oils, attributed to the formation of stable subnetwork based on the chain entanglement of the grafted fluoropolymer and PFPE oil.

Methacrylated alkali lignin grafted P(Nipam-Co-AAc) copolymeric hydrogels: Tuning the mechanical and stimuli-responsive properties

The current study reports the preparation of lignin grafted temperature and pH responsive hydrogels through copolymerization of N-isopropylacrylamide, acrylic acid and varying amount of lignin methacrylate (LMA = 50, 100, 150 and 200 mg) as crosslinker adopting radical polymerization technique. Functional group and structural characterizations were carried out to confirm hydrogels synthesis and their network structure. The variation in pore size on addition of lignin revealed the tuning of pores as well as swelling capacity of the hydrogels by suitable amount of LMA. All LMA grafted hydrogels showed temperature responsive behavior and pH dependent sensitivity in swelling, with reduced equilibrium swelling capacity values compared to sample without lignin. In alkali medium at room temperature, the maximum swelling capacity with 48% higher retention was noticed, while a significant reduction in swelling was observed at 40 °C in all media. The addition of lignin still preserved the tensile strength up to 100 kPa and compressive load bearing ability up to 30 kPa in freeze dried state with adequate interfacial stress transfer. An increase in lignin concentration showed enhanced storage modulus (~two-fold increase), adequate loss modulus values and improved cell viability, which paves the way for possible biomedical applications.

Effect of different chemical treatments and loadings of Arundo donax L. fibers on the dynamic mechanical, thermal, and morphological properties of bisphenol A aniline based polybenzoxazine composites

AbstractIn this research paper, bisphenol A aniline based benzoxazine (BA‐a) was reinforced with natural, inexpensive, and largely distributed cellulosic plant, namely Arundo donax L. (AD) at various loadings of 5, 15, and 25 wt%. AD fibers were initially subjected to three different chemical surface modifications using alkaline, silane, and combined alkali‐silane solutions. The main purpose of this work was to investigate the dynamic mechanical properties, morphological stability, and thermal stability of the as‐prepared composites by pointing out the effects of natural reinforcements treated in different ways at different loadings. Dynamic mechanical analysis of the prepared composites revealed an enhancement in storage modulus (E′) and loss modulus (E″) to higher values, especially for composites reinforced by alkali‐ or combined‐treated fibers due to the strong effect of alkaline solution to remove noncellulosic matters. Composite loaded at 25% of alkali‐silane treated AD exhibited a glass transition temperature (Tg) of 217°C, while pure polymer had a Tg of 188°C. The enhanced properties are a great indicator of the high fiber–matrix adhesion and compatibility. This conclusion is strengthened by scanning electron microscopy images. The thermal stability and degradation of the different biocomposites are also investigated by thermogravimetric analysis, revealing that the nature of the employed chemical treatment affected considerably the thermal behavior and the char yield of the composites.

Influence of microfibrillated cellulose and soft biocomponent on the morphology and thermal properties of thermoplastic polyurethanes

AbstractComposite materials from thermoplastic polyurethanes (TPUs) with biodegradable segments and microfibrillated cellulose (MFC) were developed as alternatives to traditional materials used in packaging or biomedical applications. Two TPUs were synthesized by the prepolymer method starting from different soft segments, poly(ε‐caprolactone)/poly(butylene adipate) (PUBA) or poly(ε‐caprolactone)/poly(ethylene oxide) (PUEO), and isophorone diisocyanate/aliphatic chain extender. Proton nuclear magnetic resonance (1H NMR) confirmed the structure and Fourier transform infrared spectroscopy (FTIR) along with scanning electron microscopy showed that the soft segments with different hydrophobicity led to a higher phase mixing in PUBA and improved microphase separation in PUEO. MFC was added in the TPUs with different soft segments to increase biocompatibility, strength, and degradation rate. A better thermal stability, a gradual increase of crystallinity and a better dispersion of MFC were noticed in PUEO composites compared to PUBA ones. The crystallinity increased with 78% and 50% in PUBA and PUEO composites with 5 wt% MFC compared to the neat polyurethanes showing the nucleating ability of MFC. In addition, the enhanced storage modulus, with 75% and 25% in PUEO and PUBA composites, highlighted the reinforcing efficiency of MFC. Therefore, the addition of MFC to the already synthesized TPUs allows tailoring the morphology and thermal properties of TPUs for industrial application.

Monitoring mechanical stimulation for optimal tendon tissue engineering: A mechanical and biological multiscale study.

To understand the effect of mechanical stimulation on cell response, bone marrow stromal cells were cultured on electrospun scaffolds under two distinct mechanical conditions (static and dynamic). Comparison between initial and final mechanical and biological properties of the cell-constructs were conducted over 14 days for both culturing conditions. As a result, mechanically stimulated constructs, in contrast to their static counterparts, showed evident mechanical-induced cell orientation, an effective aligned collagen and tenomodulin extracellular matrix. This orientation provides clues on the importance of mechanical stimulation to induce a tendon-like differentiation. In addition, cell and collagen orientation lead to enhanced storage modulus observed under dynamic stimulation. Altogether mechanical stimulation lead to (a) cell and matrix orientation through the sense of the stretch and (b) a dominant elastic response in the cell-constructs with a minor contribution of the viscosity in the global mechanical behavior. Such a correlation could help in further studies to better understand the effect of mechanical stimulation in tissue engineering.

Effect of stereochemistry on nanoscale assembly of ABA triblock copolymers with crystallizable blocks

We report on the nanoscale assembly of poly(lactic acid)-b-poly(ethylene oxide)-b-poly(lactic acid) (PLA-PEO-PLA) triblock copolymers in water, focusing on the effect of stereochemistry, where the PLA blocks are statistical copolymers of l-lactide and d-lactide with l/d ratios of 100/0, 95/5, 90/10, 85/15, 75/25, and 50/50. Small-angle neutron scattering (SANS) shows a nearly constant d-spacing as concentration varies in triblock systems with l/d ratios of 90/10 and 95/5, which we attribute to inhomogeneity in the structure of these gels, supported by previous USANS and confocal microscopy studies. The SANS data fit well to a core-shell ellipsoid form factor model with a hard-sphere structure factor. Polymeric micelles with l/d ratios from 75/25 to 85/15 displayed very high aggregation numbers, consistent with a strong interaction between PLA chains and the enhanced storage modulus observed in rheological studies of these systems. While the 90/10 and 95/5 samples showed lower aggregation numbers, their SANS profiles shows close spacing between micelles, which may promote a high fraction of intermicellar bridging chains, also consistent with a higher storage modulus. Overall, these results provide insight into the micellar assembly behavior of block copolymers with a crystallizable block, and indicate that tuning stereochemistry of PLA-based block copolymers is an effective means of modifying micellar properties for specific applications.

Fabrication and characterization of an injectable reinforced composite scaffold for cartilage tissue engineering: an in vitro study

There are limitations in current medications of articular cartilage injuries. Although injectable bioactive hydrogels are promising options, they have decreased biomechanical performance. Researchers should consider many factors when providing solutions to overcome these challenges. In this study, we created an injectable composite hydrogel from chitosan and human acellular cartilage extracellular matrix (ECM) particles. In order to enhance its mechanical properties, we reinforced this hydrogel with microporous microspheres composed of the same materials as the structural building blocks of the scaffold. Articular cartilage from human donors was decellularized by a combination of physical, chemical, and enzymatic methods. The decellularization efficiency was assessed by histological analysis and assessment of DNA content. We characterized the composite constructs in terms of storage modulus, gelation time, biocompatibility, and differentiation potential. The results showed that mechanical behavior increased with an increase in microsphere content. The sample that contained 10% microsphere had an enhanced storage modulus of up to 90 kPa. Biocompatibility and preliminary differentiation investigations revealed that this composite hydrogel might have potential benefits for cartilage tissue engineering.

Investigation of crosslinking ability of sodium metabisulphite with polyvinyl alcohol–corn starch blend and its applicability as wood adhesive

ABSTRACT Polyvinyl alcohol (PVA) blended corn starch (S), finds application as a water-based wood adhesive and crosslinking is a tool for enhancing properties. The study investigates the effectiveness of a novel crosslinker, Sodium metabisulphite in PVA/S blend system, and its effect on adhesive properties. The hydroxyl groups of PVA/S react with the crosslinker forming a cross-linked network. The modified blend is formulated with polyvinyl acetate (PVAc) binder, plasticiser and preservatives. Physical properties like viscosity and stability of adhesives have been evaluated in addition to tensile strength on various wooden substrates. Mechanical properties studied using pencil hardness test and ultimate stress of adhesive films showed the enhancements in the mechanical strength of films with the crosslinker. Thermo-mechanical properties studied by dynamic mechanical analysis (DMA) showed enhancement in storage modulus with an increase in glass transition temperature. The modified adhesive showed better cohesion, enhanced tensile strength with excellent stability. In conclusion, the modified adhesive showed better physical, mechanical, thermal and adhesive properties. Hence, this study can be potential in the development of starch incorporated wood adhesives.

Fabrication and Characterization of Polysaccharide Metallohydrogel Obtained from Succinoglycan and Trivalent Chromium.

In the present study, a polysaccharide metallohydrogel was successfully fabricated using succinoglycan and trivalent chromium and was verified via Fourier transform infrared spectroscopy, differential scanning calorimetry analysis, thermogravimetric analysis (TGA), field emission scanning electron microscopy, and rheological measurements. Thermal behavior analysis via TGA indicated that the final mass loss of pure succinoglycan was 87.8% although it was reduced to 65.8% by forming a hydrogel with trivalent chromium cations. Moreover, succinoglycan-based metallohydrogels exhibited improved mechanical properties based on the added concentration of Cr3+ and displayed a 10 times higher compressive stress and enhanced storage modulus (G′) of 230% at the same strain. In addition, the pore size of the obtained SCx could be adjusted by changing the concentration of Cr3+. Gelation can also be adjusted based on the initial pH of the metallohydrogel formulation. This was attributed to crosslinking between chromium trivalent ions and hydroxyl/carboxyl groups of succinoglycan, each of which exhibits a specific pH-dependent behavior in aqueous solutions. It could be used as a soft sensor to detect Cr3+ in certain biological systems, or as a soft matrix for bioseparation that allows control of pore size and mechanical strength by tuning the Cr3+ concentration.

Thermomechanical Properties of Carbon Fabric Reinforced Epoxy Laminates with h-BN and MoS2 Fillers

Abstract This work endeavors to investigate thermomechanical performance of carbon fabric reinforced epoxy composite (CEC) with fillers – hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2). The filler of 2, 4, 6, and 8 Wt.% was dispersed precisely in the epoxy resin through magnetic stirring and ultrasonication, prepared the filler loaded CEC using vacuum bag technique and studied the composite behavior at an elevated temperature by dynamic mechanical analysis. The 6 Wt.% MoS2-CEC showed 70% enhancement of storage modulus since the filler in the epoxy networks increased the composite stiffness. The increase in G-band intensity of Raman spectra in the filler loaded composites confirmed the improved matrix-fiber stress transfer. The 4 Wt.% BN-CEC revealed the highest glass-transition temperature 92°C. The thermogravimetric analysis of the composite exhibited a two-step thermal decomposition: epoxy matrix (nearby 260°C) and carbon fibers (beyond 420°C). The 4 Wt.% MoS2-CEC showed the maximum degree of crosslinking, twice the neat CEC, the MoS2 restrained the mobility of the epoxy chains and decreased the thermal decomposition. Both the filler loaded composites have comparable thermal stability and are significantly improved than the neat CEC. Thus, the composite containing solid lubricant filler up to 6 Wt.% shall be used for high-temperature applications.

Enhanced Thermomechanical Properties of ZrO2 Particle Reinforced Epoxy Nanocomposite

The present work is focused on the outcome of ZrO2 nanoparticle content variation over viscoelastic, mechanical and thermal properties of epoxy resin. For this, ZrO2–epoxy nanocomposites were prepared using ultrasonic dual mixing technique that consists of simultaneous employing ultrasonic mixing with a rotating impeller. For dynamic mechanical analyses (DMA), a single cantilever mode measurement was performed on neat as well as ZrO2–epoxy nanocomposites to determine the storage modulus, tanδ value and glass transition temperature. Cross-linking density in the rubbery region of composite materials was also identified by DMA analyses. Tensile properties of prepared nanocomposites were measured using universal tensile machine. 4 wt.% ZrO2–epoxy nanocomposite material gives maximum enhancement in storage modulus and tensile strength about 70 and 34% as compared to neat epoxy. Thermal gravimetric analysis (TGA) revealed the improved thermal stability of ZrO2–epoxy composite materials. The uniformity of ZrO2 nanoparticles distribution in epoxy matrix was examined using field emission scanning electron microscopy (FESEM).

Rheology–morphology interrelationship in high-density polyethylene/polyamide-6 microfibrillar composites

Due to the importance of rheology and morphology of microfibrillar reinforced composites (MFCs), a study has been conducted on MFCs based on high-density polyethylene (HDPE) and polyamide-6 (PA-6) using scanning electron microscope and dynamic rheometer. In the absence of an interfacial modifier and at 10 wt% concentration of the dispersed phase (PA-6), two principal factors, elongational deformation and coalescence, were found to be controlled by viscosity and elasticity ratios of the pure constituents accounting for the observed morphology of MFCs. The developed microfibrillar morphology remarkably influenced the viscoelastic properties of MFCs. It was observed that when the viscosity ratio approached unity and the elasticity ratio was minimal, the extent of coalescence in composite was significant. The rheological assessment showed enhanced storage modulus and complex viscosity upon microfibrils formation. This was more pronounced for samples with thinner microfibrils due to more strongly entangled network, compared to the composites with thicker microfibrils. The length-to-diameter ratio of the microfibrils could not be estimated due to their highly asymmetric length scale.

Construction of micro-thermal conductive network of self-assembled CNTs hybrids with 1D–0D structure

In this context, carbon nanotubes (CNTs)/silver nanoparticles hybrids with special 1-dimensional–0-dimensional (1D–0D) structure were successfully fabricated via self-assemble of dopamine followed by reduction reactions of silver cations aiming to synthesize more efficient thermal conductive fillers for the formation of heat flow transfer network in PA6 matrix. FTIR, XRD, TG and TEM revealed the characteristics of functionalized CNTs. Meanwhile, the effect of CNTs hybrids with 1D–0D structure on the construction of heat flow network and thermal conductivity was also investigated. Experimental results showed that thermal conductivity of composites enhanced with increased filler content, the highest thermal conductivity of the PA6/CNTs hybrids composites reached 0.65 W m−1 K−1, which was 2.1 times that of pure PA6 and 32% higher than that of pristine CNTs-filled composites (0.55 W m−1 K−1) with same filler content (10 vol%), and this was ascribed to the better dispersion of fillers and enhanced interfacial interaction between fillers and matrix, as well as the special structure of CNTs hybrids that could abundance the heat transfer path. The crystallinities and dynamic thermal mechanical properties were also analyzed. The enhanced storage modulus (1940 MPa for pure PA6 to 3650 MPa for PA6/CNTs hybrids composites at 5 °C) and higher glass transition temperature along with the change of crystallization behavior of fabricated composites were in accordance with the thermal conductive behavior. The thermal conductive model and its mechanism were then proposed and further confirmed by scanning electron microscopy.

Hybrid gelatin/oxidized chondroitin sulfate hydrogels incorporating bioactive glass nanoparticles with enhanced mechanical properties, mineralization, and osteogenic differentiation

Biopolymer based hydrogels are characteristic of their biocompatibility and capability of mimicking extracellular matrix structure to support cellular behavior. However, these hydrogels suffer from low mechanical properties, uncontrolled degradation, and insufficient osteogenic activity, which limits their applications in bone regeneration. In this study, we developed hybrid gelatin (Gel)/oxidized chondroitin sulfate (OCS) hydrogels that incorporated mesoporous bioactive glass nanoparticles (MBGNs) as bioactive fillers for bone regeneration. Gel-OCS hydrogels could be self-crosslinked in situ under physiological conditions in the presence of borax. The incorporation of MBGNs enhanced the crosslinking and accelerated the gelation. The gelation time decreased with increasing the concentration of MBGNs added. Incorporation of MBGNs in the hydrogels significantly improved the mechanical properties in terms of enhanced storage modulus and compressive strength. The injectability of the hydrogels was not significantly affected by the MBGN incorporation. Also, the proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells in vitro and rat cranial defect restoration in vivo were significantly promoted by the hydrogels in the presence of MBGNs. The hybrid Gel-OCS/MBGN hydrogels show promising potential as injectable biomaterials or scaffolds for bone regeneration/repair applications given their tunable degradation and gelation behavior as well as favorable mechanical behavior and osteogenic activities.

Poly(propylene carbonate)/clay nanocomposites with enhanced mechanical property, thermal stability and oxygen barrier property

To develop eco-polymeric materials is of significant importance to protect the global environment and promote the sustainable development of human society. Poly (propylene carbonate) (PPC) as a new biodegradable polymer has attracted much interest, but some properties of PPC have to be improved before the practical utilization.In this work, the re-dispersible unmodified laponite and montmorillonite (MMT) were used as the nanometer reinforcing phase to enhance the mechanical property, thermal stability and oxygen barrier property of PPC. Via a simple solution mixing method, the PPC/laponite and PPC/MMT nanocomposites were fabricated. The unmodified laponite and MMT were well dispersed in the PPC matrix, which was confirmed by TEM results. As a result, the obtained PPC/clay nanocomposites exhibited high transparency (>80%) and enhanced storage modulus (100–150% higher than PPC), when the clay content was in a range of 1–10 wt%. In addition, the incorporation of lower than 3 wt% of laponite and MMT increased the elongation at break and thermal stability of PPC. The initial decomposition temperature (Td10%) of PPC/clay nanocomposites with 1 wt% clay was approximately 250 °C, which was substantially higher than that of pure PPC (215 °C). The PPC/clay nanocomposites with 7 wt% clay displayed the lowest O2 permeability, which was two orders of magnitude lower than that of pure PPC. Therefore, the resultant PPC/clay nanocomposites with enhanced properties have a potential to boost the practical utilization of PPC.