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This study compares the mechanical properties of recycled high-density polyethylene (r-HDPE)/rice husk (RH) composites from a twin-screw extruder and a heated two-roll mill, and the effect of different filler loadings using different melt blending processes on the mechanical properties of r-HDPE/RH composites. Polyethylene-graft-maleic anhydride (MAPE) acts as the coupling agent to enhance interfacial bonding between the fibre and the polymer matrix. The filler loading used was in the range of 10-40 wt. %. In this work, r-HDPE/RH blends were prepared using a twin-screw extruder and a heated two-roll mill. The ratio of 70/30 twin-screw extruder compounded composites significantly showed higher tensile based on improved to about 45.5% at 11 MPa compared to those compounded in the heated two-roll mill. The same ratio showed an increment almost up to 9% of elongation at break. It has also been verified that the higher filler loading used reduced the tensile strength and elongation at break, while the Young’s modulus increased. The result was evidenced by the increase in water absorption and longer burning time as the filler loading increased.

In this study, the effects of polyaniline (PANI) incorporation (3 wt% of PANI) and graphene nanoplatelets (GNPs) loading (0.1–0.7 wt%) on the mechanical, thermal, and electrical performance of epoxy matrix were investigated. The incorporation of 0.3 wt% GNPs optimally enhanced the bending strength, bending modulus, tensile strength, tensile modulus, and impact strength (90 MPa, 1422 MPa, 63 MPa, 602 MPa, and 8.29 kJm−2, respectively). At 0.3 wt% GNPs, the hybridization effect optimally enhanced the glass transition behaviour of the epoxy nanocomposites. The electrical and thermal conductivities of epoxy were improved upon the inclusion of PANI, and this increase was further augmented when the GNPs content increased to 0.3 wt%. However, higher GNPs contents deteriorated the mechanical performance and electrical and heat conduction. Field emission scanning electron microscopy showed good filler distribution and effective interactions among the GNPs, PANI, and epoxy components with appropriate compositions.

This study investigates the novel effect of poly(lactic acid) (PLA) optical purity on PLA/liquid natural rubber (LNR) blend films fabricated by solution casting. An investigation was conducted to examine how different levels of PLA optical purity affect the mechanical, structural, morphological, thermal, and barrier properties of PLA/LNR films. Infrared spectroscopy analysis revealed that the D‐isomer content of PLA significantly affected the chemical interactions between the LNR and PLA. The favorable chemical interaction between the LNR and PLA with a high D‐isomer content also increased the elongation at break by 300%. Morphological investigations proved that the chemical interaction also improved the dispersion and reduced the size of the LNR droplets formed in the PLA matrix. Notably, while low D‐isomer PLA blends showed decreased crystallinity (Xc) upon LNR addition, high D‐isomer PLA blends exhibited increased Xc by 460%, leading to a 42% increase in oxygen transmission rate. Additionally, hydrolytic degradation of high D‐isomer PLA increased by 259% with increasing LNR content. Overall, optical purity of PLA plays an important role in determining the properties of PLA blends. [ABSTRACT FROM AUTHOR]

Plastic wastes have caused serious environmental issues worldwide, and thus viable solutions for their replacement are now urgently needed. This work aimed to develop biocomposite materials based on polyethylene (PE) wastes as matrix reinforced with coconut fiber, without any additional chemical treatments, using extrusion and compression molding. The effects of polymer matrix type (high-density and low-density PE (HDPE and LDPE)) and fiber loading (5-15 wt%) on the mechanical properties and long-term water absorption behaviour of the materials were evaluated. Tensile strength results showed the optimum performance at 5 wt% fiber -- of 16.6 MPa for the HDPE matrix and 7.3 MPa for the LDPE matrix, but flexural and impact strengths reduced with the fiber loading. An increasing trend of water absorption capacity was noted as a function of filler loading and of the water temperature during immersion, with a weight gain of up to 5%, following the trend: cold water > room temperature tap water > hot water. From the results, HDPE based biocomposites had better mechanical performance and lower water absorption capacity, compared with LDPE based biocomposites. [ABSTRACT FROM AUTHOR]

We have demonstrated the significant impact of high density polyethylene (HDPE) crystallinity and structural morphology on the tensile strength of 60/40 NR/HDPE polymer blend composites. Introducing nanoscale Boron Carbide (B4C‐type compounds) fillers noticeably changed the crystallinity and morphology of HDPE, leading to the formation of fine spherulites. Conversely, microscale fillers mainly impacted the crystallinity while preserving a coarse architecture. Although both composites experienced a reduction in crystallinity, the nanocomposites outperformed microcomposites and even the pristine polymer blend in terms of strength, implying the effect of a fine structure. The nanocomposite with a filler loading of 2 wt% exhibited the highest strength. This investigation provides novel insights into the interplay between crystallinity, HDPE structure, and the size of fillers, which heavily influence the strength of polymer blend composites. [ABSTRACT FROM AUTHOR]

Linear low‐density polyethylene (LLDPE) is widely used in industries. It possesses remarkable characteristics such as low density, easy to process, and recyclable. However, LLDPE‐based products are known to be highly permeable to water and oxygen, thus limiting their application as packaging material. In this study, natural rubber (NR) and graphene nanoplatelets (GNP) were mixed with LLDPE to produce thermoplastic elastomer nanocomposites films as a novel, potential packaging material with the aid of liquid natural rubber (LNR) as compatibilizing agent. The formulation modification of GNP, NR, and LNR components influenced the mechanical and barrier properties of the resulting nanocomposites. The mixing methods, i.e., direct melt‐mixing and masterbatch mixing (MB) were also investigated. Apparently, tensile test for samples prepared from MB mixing method yielded better results compared to samples from direct melt‐mixing. Permeability tests of water vapor (WVP) and oxygen (OTR) demonstrated that LLDPE/GNP/NR/LNR nanocomposites films managed to reduce the permeability rate of WVP and OTR of pure LLDPE by 92.73% and 98.60%, respectively. The tortuous theory had been confirmed that the experimental data best fit the Nielsen model at aspect ratio of 20, 30 and 10, 20, 40, 200 for WVP and OTR, respectively. [ABSTRACT FROM AUTHOR]

Over the last few decades, processing and compatibility have become challenging and interesting investigation areas of polymer matrix nanocomposites. This study investigated the addition of maleic anhydride (MAH) at different ratios with graphene nanoplatelets (GnPs) in poly(lactic acid)/modified natural rubber/polyaniline/GnP (PLA/m-NR/PANI/GnP) nanocomposites via two processing methods: a two-step technique and a one-pot technique. The former technique involved first preparing a master batch of PLA grafted with MAH, followed by a second step involving the melt blending of the nanocomposite (T1) using MAH-g-PLA. On the other hand, the one-pot technique involved the direct mixing of MAH during the melt-blending process (T2). The mechanical, morphological and thermal properties of the prepared nanocomposites were investigated. The findings showed that adding MAH significantly improved the tensile strength and elongation at break by about 25% for PLA/m-NR/PANi/GnP nanocomposites, with an optimal ratio of 1:1 of MAH-g-PLA to GnP loading using the T1 technique. FTIR analysis confirmed the chemical interaction between MAH and PLA for T1 nanocomposites, which exhibited improved phase morphology with smoother surfaces. MAH-compatibilized nanocomposites had enhanced thermal stabilities when compared to the sample without a compatibilizer. The findings show that the compatibilized PLA nanocomposite is potentially suitable for bio-inspired materials. [ABSTRACT FROM AUTHOR]

Developing a bio‐based polyol polyurethane foam with the desired properties for use as growing media for green vertical walls could be beneficial in the quest to create a more sustainable urban living. In this work, palm kernel oil‐based polyol (PKOP) was mixed with petroleum‐based polyol (PP) at different ratios in synthesizing polyurethane foam. The impacts of PKOP/PP formulation on the density, cell morphology, water absorption, water retention, swelling behavior, and their chemical functional groups were evaluated. It was determined that replacing PP with low levels of PKOP could reduce the water absorption ability due to the introduction of hydrophobic plant‐based fatty acids. On the contrary, polyurethane foam containing more than 30% PKOP has improved the water absorbing ability and retention properties. Fourier‐transform infrared (FTIR) spectrum indicates that the synthesized foams are isocyanate‐free and stable toward pH changes. The trial planting attempt was a success where the plants were grown from seeds using the synthesized foam media. It was proposed that 50% PKOP is most suitable for use as a growing media, based on its water absorbing and retention properties. The findings of this study highlight the potential for the use of bio‐based polyol polyurethane foam for more sustainable growing media in urban gardens. [ABSTRACT FROM AUTHOR]

Excessive amount of disposable and reusable plastic wastes has increasingly gained a great environmental concern. This present article aims to investigate the individual effect of multiwalled carbon nanotubes (MWCNTs) and clay loadings at 0.5, 1.0, 2.0, 4.0, and 6.0 phr on the tensile, impact, density, and water absorption properties of polymer blend made from recycled high‐density polyethylene and recycled polyethylene terephthalate. Both nanocomposites were melt‐blended using a twin screw extruder before compression molding. For MWCNT nanocomposite, 4 phr showed the optimum tensile strength (14.5 MPa), Young's modulus (587.4 MPa), and strain at break (4.2%) as compared to other loadings. For clay nanocomposite system, the optimum tensile properties (13.9 MPa tensile strength, 525.7 MPa Young's modulus, and 4.7% strain) were achieved at 1 phr. The impact strength of the nanocomposites was reduced with both nanofillers' content. With the increment of MWCNT and clay loadings, the percentages of water uptake increased but the values were still considered low (<0.26% upon 35 days immersion) capacity. These research findings with the effect of nanofiller types and loadings were statistically significant as proven in ANOVA analysis. This study formalizes a chemical‐free environmental strategy to produce nanocomposite as a plastic‐replacement product. [ABSTRACT FROM AUTHOR]

This study compares the mechanical properties of recycled high-density polyethylene (r-HDPE)/rice husk (RH) composites from a twin-screw extruder and a heated two-roll mill, and the effect of different filler loadings using different melt blending processes on the mechanical properties of r-HDPE/RH composites. Polyethylene-graft-maleic anhydride (MAPE) acts as the coupling agent to enhance interfacial bonding between the fibre and the polymer matrix. The filler loading used was in the range of 10-40 wt. %. In this work, r-HDPE/RH blends were prepared using a twin-screw extruder and a heated two-roll mill. The ratio of 70/30 twin-screw extruder compounded composites significantly showed higher tensile based on improved to about 45.5% at 11 MPa compared to those compounded in the heated two-roll mill. The same ratio showed an increment almost up to 9% of elongation at break. It has also been verified that the higher filler loading used reduced the tensile strength and elongation at break, while the Young's modulus increased. The result was evidenced by the increase in water absorption and longer burning time as the filler loading increased. [ABSTRACT FROM AUTHOR]

The research on the polymer silicate layer nanocomposites is currently focusing on maximizing the polymer‐filler interface interaction. This study aimed to elucidate the effect of two different types of montmorillonite (MMT), which were Cloisite sodium (CNa) and Cloisite 10A (C10A), on the thermal, water absorption, and mechanical performances of polylactide (PLA) nanocomposites. Nanocomposites with different clay loadings from 1 to 7 wt% were fabricated by melt intercalation in a twin‐screw extruder. XRD analysis showed an intercalated structure for PLA/C10A at 1 and 3 wt% loadings. From TGA analysis, the initial thermal degradation temperature for PLA/C10A at 1 and 3 wt% showed promising enhancement in thermal stability. DSC results also confirmed that both nanocomposites at clay loadings less than 5 wt% improved thermal properties and crystallinity compared to neat PLA. Storage modulus and tan δ for PLA/C10A shifted towards higher temperature. Water absorption intakes of PLA/C10A at 1 and 3 wt% loadings were reduced by 42% and 39%, respectively. For PLA/C10A at the optimum loading of 3 wt%, tensile strength improved by 21% and strain by 17%. This loading exhibited the finest morphological structure. [ABSTRACT FROM AUTHOR]

In this study, graphene nanoplatelets (GNP) of 0.2%–1.0% by weight were introduced to the rubber toughened epoxy matrix with via a direct method. The effect of GNP loadings on the mechanical (tensile and impact properties) and thermal properties of the rubber toughened epoxy/GNP nanocomposites were evaluated. The results showed that the incorporation of GNP had optimally improved the tensile strength and tensile modulus by 70% and 74%, respectively, at 0.6 wt% filler loading. Thermogravimetric analysis (TGA) and Tg increment result proved the barrier effect via delaying decomposition process which induced by the layered structure of GNP and thus significantly enhanced the thermal stability of epoxy‐based resin, irrespective of GNP loadings (insignificant difference in the decomposition temperature). The fractured surfaces of these nanocomposites showed the good interfacial interaction between the matrix and the GNP nanofiller. X‐ray diffraction (XRD) analysis demonstrated the exfoliation and intercalation states of GNP dispersion in epoxy/LENR. [ABSTRACT FROM AUTHOR]

Enormous amounts of plastic wastes are generated worldwide and the approaches related to plastic recycling or reusing have become the research focus in the field of composite materials. In this study, green composites were prepared via melt-blending method using high-density polyethylene (HDPE) sourced from plastic bags as a matrix and sugarcane bagasse (SCB) fiber as reinforcing filler. The effects of fiber loading (5, 10 and 15 wt%) and fiber modification on the mechanical and dimensional stability (weight gain by water absorption) properties of the green composites were investigated. Results showed that the inclusion of SCB fiber into recycled HDPE matrix increased the composite stiffness but decreased the mechanical strength and resistance to water absorption. With the fiber modification through alkali treatment, the mechanical strength was remarkably improved, and the modulus and water absorption of the composites were found to be reduced. From the finding, it can be concluded that the prepared green composites free of coupling agent could add value to the plastic and agricultural wastes, and serve a potential candidate to replace some conventional petroleum-based composites. [ABSTRACT FROM AUTHOR]

The essence core of this study is to investigate the effect of functionalization of graphene platelets (GNPs) and its low loadings of 0.25, 0.50, 0.75, and 1.00 wt% on the chemical, mechanical, and electrical properties of polylactic acid/liquid natural rubber (PLA/LNR) blend prepared by melt blending method. GNPs are treated with amino dodecanoic acid via covalent interaction and Triton X‐100 (TX100) via non‐covalent interaction to produce ADA‐functionalized GNPs (GNP‐A) and TX100‐functionalized GNPs (GNP‐T), respectively. At 0.75 wt% GNPs, the PLA/LNR nanocomposites exhibit the highest tensile strength of 24.38, 35.70, 45.47 MPa for untreated GNPs (GNP‐u), GNP‐T, and GNP‐A, respectively. Variable pressure scanning electron microscopy proves better interaction of treated‐GNPs with the matrix, while transmission electron microscopy micrographs have shown that PLA/LNR/GNP‐A has the best filler dispersion with minimal stacking and agglomeration found. A remarkable improvement of electrical properties is observed for treated‐GNPs nanocomposite with lower percolation threshold value of 0.3 wt% as compared to that of GNP‐u nanocomposite (0.4 wt%). [ABSTRACT FROM AUTHOR]

A high loading rice husk fibre (RHF) incorporated polyolefin blend of recycled polyethylene high-density/poly(ethylene terephthalate) (rPEHD/rPET) biocomposite was produced through extrusion and hot/cold press process. Interfacial modification of biocomposites was conducted through alkalization (sodium hydroxide solution) of fibres, compatibilization (using E-GMA) and/or coupling agent (MA -g -PE) to improve the interaction between components and the homogeneity of materials blending. Alkalization of fibres had improved the impact strength of biocomposites. The compatibilization and coupling effects on immiscible rPEHD/rPET blend and recycled polymer/RH filler, respectively, had led to an enhancement of mechanical performance and morphological stability. Scanning electron microscope micrograph revealed the improved matrix–matrix and filler–matrix interaction through interfacial modification. This investigation had shown that RHF mixed well with rPEHD/rPET/RHF to produce eco-friendly biocomposite products. [ABSTRACT FROM AUTHOR]

Conventional polymer blending has a shortcoming in conductivity characteristic. This research addresses the preparation of conductive thermoplastic natural rubber (TPNR) blends with graphene nanoplates (GNPs)/polyaniline (PANI) through melt blending using an internal mixer. The effect of PANI content (10, 20, 30, and 40 wt %) on the mechanical and thermal properties, thermal and electrical conductivities, and morphology observation of the TPNR/GNPs/PANI nanocomposites was investigated. The results showed that the tensile and impact properties as well as thermal conductivity of nanocomposite had improved with the incorporation of 3 wt % of GNPs and 20 wt % of PANI as compared to neat TPNR and reduced with further increase of the PANI content. It was observed that the GNPs and PANI acted as a critical component to improve the thermal stability and electrical conductivity of the TPNR/GNPs/PANI nanocomposites. The most improved conductivity of 5.22 E‐5 S/cm was observed at 3 wt % GNPs and 40 wt % PANI. Variable‐pressure scanning electron microscopy micrograph revealed the good interaction and distribution of GNPs and PANI within TPNR matrix at PANI loadings lower than 30 wt %. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48873. [ABSTRACT FROM AUTHOR]

High-fiber loading green composites were prepared from recycled high-density polyethylene (rHDPE)/recycled polyethylene terephthalate (rPET) blend matrix and rice husk (RH) as filler (from 40 wt% up to 80 wt%) via corotating twin-screw extruder and compression molding. The water absorption (WA) upon immersion in sea water, mechanical behavior, and combustion enthalpy of green composites were examined. The WA mechanisms obeyed the Fickian diffusion. The computed diffusion coefficient (D), thermodynamic solubility (S), permeability (P), and orthotropic swelling were generally increased as a function of RH filler. The increment of tensile strength and modulus of composites were maximized up to 16% and 121%, respectively, which was achieved at 70 wt% RH filler. The theoretical prediction of tensile strength and Young's modulus from micromechanical models for random oriented RH fiber/blend composites were compared with the experimental results. As the RH weight fraction increased, the combustion enthalpy decreased (by approximately 30–48%) and thereby the enhancing the fire retardancy of green composite. [ABSTRACT FROM AUTHOR]

Thermoplastic natural rubber (TPNR) was compounded with graphene nanoplatelets (GNP) via ultrasonication and melt blending. The effects of ultrasonication period (1-4 hours) and GNP weight fraction (0.5, 1.0, 1.5 and 2.0 wt.%) on the mechanical, thermal and conductivity properties were investigated. Results showed that the 3 hours of ultrasonic treatment on LNR/GNP gave the greatest improvement in tensile strength of 25.8% (TPNR/GNP nanocomposites) as compared to those without ultrasonication. The TPNR nanocomposites containing 1.5 wt.% GNP exhibited the highest strength (16 MPa for tensile, 14 MPa for flexural and 11 kJm-2 for impact) and modulus (556 MPa and 869 MPa for tensile and flexural, respectively). The incorporation of GNP had enhanced the thermal stability. It can be concluded that the GNP had imparted the thermally and electrically conductive nature to the TPNR blend. [ABSTRACT FROM AUTHOR]

The thermal conductivity and mechanical performance of a hybrid multi‐walled carbon nanotubes/silicon carbide (MWCNTs/SiC)‐reinforced thermoplastic natural rubber (TPNR) nanocomposite were investigated. TPNR was fabricated from polypropylene, natural rubber (NR) and liquid NR at a volume ratio of 70:20:10, respectively. The Young's modulus, the tensile strength, and the storage and loss modulus of the nanocomposites with a single filler of MWCNTs or SiC were enhanced compared with those of neat TPNR. The greatest improvements in these properties were achieved at a composition of 1.5 wt% SiC‐1.5 wt% MWCNTs‐reinforced nanocomposite. In addition, the thermal conductivity and specific heat capacity of the nanocomposites, determined using a laser flash technique, were improved in the 3 wt% SiC‐reinforced nanocomposite sample relative to those of the pure sample and the other reinforced nanocomposites. Based on these findings, MWCNTs and SiC could serve as suitable percolated networks of hybrid reinforcement fillers to achieve optimal thermal and mechanical properties in the TPNR matrix. POLYM. COMPOS., 40:E695–E703, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Green composite materials were made from agricultural and plastic wastes which were rice husk (RH), recycled high‐density polyethylene (rHDPE), and recycled polyethylene terephthalate (rPET), by twin‐screw extrusion and hot/cold pressing molding. The dimensional stability, orthotropic swelling, and mechanical performance of the green composites were determined as a function of bio‐filler concentration for neat (uncompatibilized) and compatbilized rHDPE/rPET blend based composites. Water absorption and swelling results showed a linear increase with the RH concentration. The highest swelling occurred in the thickness of the composites, followed by the width and length, respectively. Water absorption and dimensional instability of compatibilized recycled polymer blend (rPB)‐based composites were lower than those of neat rPB‐based composites. As RH concentration increased, the flexural properties increased significantly. The optimum tensile strength and modulus were achieved at 70 wt% RH. It is interesting to note that compatibilization of polymer blend matrix had further increased the strength and elongation properties of composites. POLYM. COMPOS., 39:2695–2704, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix. [ABSTRACT FROM AUTHOR]

This article studies the enhancement in the properties of thermoplastic natural rubber (TPNR) reinforced by graphene oxide (GnO) and multiwalled carbon nanotubes (MWCNTs). TPNR is a blend of polypropylene and liquid natural rubber (NR), which is used as a compatibilizer and NR at a percentage of volume ratio 70:10:20, respectively. Using TPNR as the host matrix, a number of TPNR/carbon nanotubes (CNTs), TPNR/GnO, and hybrid TPNR/GnO/CNTs nanocomposites are processed and their mechanical, thermal, and electrical properties are characterized. The results extracted from tensile and impact test showed that tensile strength, Young’s modulus, and storage modulus of TPNR/GnO/MWCNTs hybrid nanocomposite increased as compared with TPNR composite and TPNR/GnO nanocomposite but lower than TPNR/MWCNTs nanocomposite. On the other hand, the elongation at break considerably decreased with increasing the content of both types of nanoparticles. Based on the experimental results, the thermal, electrical conductivity of a 0.5 wt% MWCNTs-reinforced sample increased as compared with a pure TPNR and other MWCNTs/GnO-reinforced composites. The improved dispersion properties of the nanocomposites can be due to altered interparticle interactions. MWCNTs, GnO, and MWCNTs–GnO networks are well combined to generate a synergistic effect that is shown by scanning electron microscopy micrographs. With the existence of this network, the mechanical, thermal, and electrical properties of the nanocomposite were improved significantly. [ABSTRACT FROM AUTHOR]

Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet–visible (UV–Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products. [ABSTRACT FROM AUTHOR]