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Cryphalus piceae parasitizes various economically important conifers. Similar to other bark beetles, C. picea vectors an assortment of fungi and nematodes. Previously, several ophiostomatoid fungi were isolated from C. piceae in Poland and Japan. In the present study, we explored the diversity of ophiostomatoid fungi associated with C. piceae infesting pines in the Shandong Province of China. We isolated ophiostomatoid fungi from both galleries and beetles collected from our study sites. These fungal isolates were identified using both molecular and morphological data. Through this study, we recovered 176 isolates of ophiostomatoid fungi representing at least seven species. Ophiostoma ips was the most frequently isolated species. Analyses of molecular and morphological data indicated four of the ophiostomatoid fungal species recovered in this study were previously undescribed. Hereby, we described these species as Ceratocystiopsis yantaiensis sp. nov., C. weihaiensis sp. nov., Graphilbum translucens sp. nov. and Sporothrix villosa sp. nov. A majority of the ophiostomatoid fungi recovered in this study were novel species. This suggests that the forests in China harbour an assortment of undescribed ophiostomatoid fungi yet to be discovered.

Cryphalus piceae attacks various economically important conifers. Similar to other bark beetles, Cr. piceae plays a role as a vector for an assortment of fungi and nematodes. Previously, several ophiostomatoid fungi were isolated from Cr. piceae in Poland and Japan. In the present study, we explored the diversity of ophiostomatoid fungi associated with Cr. piceae infesting pines in the Shandong Province of China. We isolated ophiostomatoid fungi from both galleries and beetles collected from our study sites. These fungal isolates were identified using both molecular and morphological data. In this study, we recovered 175 isolates of ophiostomatoid fungi representing seven species. Ophiostoma ips was the most frequently isolated species. Molecular and morphological data indicated that five ophiostomatoid fungal species recovered were previously undescribed. Thus, we proposed these five novel species as Ceratocystiopsis yantaiensis, C. weihaiensis, Graphilbum translucens, Gr. niveum, and Sporothrix villosa. These new ophiostomatoid fungi add to the increasing number of fungi known from China, and this evidence suggests that numerous novel taxa are awaiting discovery in other forests of China.

This study investigated the sublimation of Mn and microstructural evolution of binary Fe/Mn compacts sintered at various temperatures in a vacuum. A high sintering temperature or a lengthy holding time promotes powder densification. Due to sublimation of Mn, the weight loss of the compacts mainly occurs during the isothermal holding stage of the sintering process; it increases significantly from 1.5 wt.% for sintering at 1000 °C to 8.6 wt.% at 1200 °C. For the first time, the phase evolution in the binary elemental compacts was clarified using in situ neutron diffraction. The γ-austenite phase emerges during temperature ramping to 536 °C, while β-Mn and α-Fe disappear at 774 °C and 881 °C. The neutron diffraction also revealed that single phase γ-austenite forms in the Fe-Mn compacts if the temperature is ≥ 881 °C.

This work investigated the effects of current density and deposition time on the properties of electrodeposited PbO2. The PbO2 preparation was conducted on Ti/SnO2–Sb substrates by galvanostatic anodic deposition in a newly proposed methanesulfonate electrolytic solution. Phase constituents and microstructures of the deposited PbO2 coatings were characterized. Increasing current density in the range ≤ 100 mA cm− 2 leads to the formation of highly textured coatings with an increased content of α-PbO2 phase. Concurrently, a high current density favors a compact and flat surface morphology. The study of deposition time indicates a change of crystallite growth manner from an initially random growth to a later-stage preferred growth along distinct orientations. The change of crystallite growth is corroborated by the cross-sectional microstructures of the PbO2 deposits. The microstructural transition occurs only in the initial deposition stage. After a brief period, prolonged electrodeposition barely changes the surface morphology of PbO2 coatings.

A novel flexible nickel–cobalt layered double hydroxide/polyaniline/bacterial cellulose (NiCo-LDH/PANI/BC) electrode with both excellent electrochemical and mechanical performances is obtained through successively coating PANI and NiCo-LDH on BC. In addition to making the 3D open network (BC) conductive, the PANI layer also functions as a “nanoglue” to uniformly and robustly immobilize nanostructured NiCo-LDH onto the highly enlarged surface of PANI/BC nanofibers owing to its rough surface and hydrophilicity. Benefitting from the hierarchical structure with a 3D conductive network, unobstructed channels, numerous electroactive sites and induced synergistic effect, the NiCo-LDH/PANI/BC electrode shows excellent electrochemical performance in an aqueous electrolyte, exhibiting a high specific capacitance of 1690 F g−1 (761 C g−1) at 1 A g−1, enhanced rate capability (778 F g−1 or 350 C g−1 at 15 A g−1) and outstanding cycling stability (83.2% capacitance retention after 5000 cycles). Besides, the NiCo-LDH/PANI/BC also shows excellent foldability, high tensile strength (90.8 ± 4.9 MPa), high elongation at break (7.2 ± 0.7%) and outstanding electrochemical stability during bending and stretching. Moreover, a flexible all-solid-state supercapacitor is assembled with NiCo-LDH/PANI/BC as the positive electrode and N-doped carbonized BC/carbon cloth as the negative electrode, delivering a high energy density of 47.3 W h kg−1 at a power density of 828.9 W kg−1, and superior cycling stability (91.4% capacitance retention after 3000 cycles). Therefore, this work provides a new path for high-performance flexible energy storage devices and offers a new vision for uniformly and robustly assembling nanohybrids.

Polyethylene glycol (PEG), with polymethyl methacrylate (PMMA) as the backbone binder component, is a common primary binder component in the design of water soluble binder systems for metal injection moulding (MIM). However, PEG crystallises upon cooling, producing voids in the injection moulded parts. These voids ultimately lead to porosity and degraded mechanical properties in the sintered bodies. We have previously reported on the use of polyvinylpyrrolidone (PVP) as a crystallisation inhibitor in the PEG/PMMA binder system to suppress void formation. In this paper, PEG/PMMA/PVP binder-based feedstocks were prepared with a 67 vol% solid loading in order to evaluate the effects of PVP incorporation on the PEG/PMMA binder for titanium MIM. The homogeneity and rheological behaviours of the feedstocks with varying amounts of PVP were compared with the base PEG/PMMA binder-based feedstock. Microstructural observation, impurity measurement and mechanical testing were carried out. It was found that incorporation of 20 wt% PVP into the PEG produced a void-free, high quality Ti-MIM component, with an average final density of 98% and a tensile elongation of 9.5%.

Free-standing and flexible activated flax fabrics (AFFs) with hierarchical meso/microporous structures have been prepared through a novel one-step synthetic strategy of rapid carbonization/activation of flax fabrics in CO2. The fast heating and the high partial pressure of CO2 inhibit the decomposition of flax fabrics during heating up, and thus keep more char materials for gasification at high temperature. It is found that such a process retains a considerable amount of oxygen groups and creates relatively large pores, bringing a one-step process to carbonize and activate flax fabrics at the same time and offering the freedom of tuning the mesopore volume/total pore volume (Vmeso/Vtotal) ratio. Notably, the Vmeso/Vtotal ratio is significantly increased from 27.6% to 67.0%. As a result, the flexible electrodes show excellent electrochemical performance in aqueous electrolyte, exhibiting a large specific capacitance (205 F g−1 or 140 F cm−3 at current density of 0.1 A g−1), a good rate capability (139 F g−1 or 95 F cm−3 at 35 A g−1), and an excellent cycling stability (∼96.6% retention after 3000 cycles). The excellent rate performance can be attributed to the improved ion transport (due to large pore size) and the good wettability (due to the oxygen group) of electrolyte.

In this work, the thermal behavior of graphene foam (GF) filled polymer composite is investigated using the finite element method. Owing to the interconnected structure of GF, which forms effective heat pathways, GF filled polymer composite is endowed with good thermal properties. The effect of contact thermal resistance, interfacial thermal conductance, as well as GF strut length and diameter on thermal conductivity is simulated and compared with experimental results. It is found that the contact thermal resistance is more important than interfacial thermal conductance in terms of thermal conductivity of composite. The contact thermal resistance between GF filled polymer composite and copper block is about 10 −4 to 10 −3 m 2 KW −1 . The shorter length and larger radius of GF struts are beneficial for heat dissipation. The results prove that the GF filled polymer composite is a good candidate material for heat management of electronic devices.

Graphene has attracted intense attention in electrochemical capacitors (ECs) as electrode material due to its excellent electronic, mechanical and thermal properties as well as its ultrahigh specific surface area. Considering the electrochemical performance of an EC is largely determined by electrode architectures, this review particularly focus on recent progress on designing and controlling the architectures of graphene based electrodes. After briefly introducing the energy storage mechanisms of ECs and the effects of pore sizes and pore size distribution on capacitance, we highlight the development and challenges for one to three dimensional graphene electrodes, their respective advantages, and corresponding electrochemical performance including specific capacitance, energy density, power density, rate capability and cyclic stability. This review also highlights the effects of introducing other electro-active materials such as carbon nanotubes, conducting polymers and metal oxides on the electrochemical performance of one to three dimensional graphene hybrid electrodes.

The effect of carbon fibre (CF) on the mechanical and thermal properties of graphene foam (GF)/polydimethylsiloxane (PDMS) composites was investigated. The CFs with different weight percentages (2, 4, 6, 8 and 10 wt%) were thoroughly dispersed in the PDMS matrix using a high-speed shearing and stirring method and then the GF was filled with the mixture. The CF/GF/PDMS composites were characterized in terms of microstructure, mechanical and thermal properties using various testing techniques. The results reveal that the addition of CF observably improved the mechanical and thermal properties of GF/PDMS composites. For 10 wt% CF/GF/PDMS composite, the tensile strength and Young's modulus are increased by 52% and 71% respectively compared with GF/PDMS composite. In addition, its thermal conductivity reaches 0.55 Wm −1 K −1 , i.e., an increase by about 41% and 162% compared to GF/PDMS composite and pure PDMS, respectively. SEM images show a strong interfacial bonding between CF and PDMS.

B, N dual-doped sisal-based activated carbon (BN-SAC) with a multiscale porous structure for high-rate supercapacitor electrode was prepared through a novel and facile strategy. With the inherent cellular channels serving as primary macropores, secondary mesopores and micropores are generated on the fiber surface and tracheid walls through low-pressure rapid carbonization of (NH4)2B4O7-containing sisal fibers and successive KOH activation. In addition to introducing B, N atoms into the BN-SAC, the additive also facilitates the formation of mesopores due to the rapid gas evaporation during its decomposition, leading to significantly increased specific surface area (2017 m2 g−1) and mesoporosity (68.6%). As a result, the BN-SAC-3 shows highly enhanced electrochemical performance including a high specific capacitance of 304 F g−1, excellent rate capability (with 72.6% retention at 60 A g−1) and superior cycling stability (4.6% capacitance loss after 3000 cycles). After assembling the BN-SAC-3 into symmetric supercapacitor, it shows a specific capacitance of 258 F g−1 at 1 A g−1 with 76.4% retention at 40 A g−1 in 6 M KOH electrolyte, and delivers a maximum energy density of 24.3 W h kg−1 at a power density of 612.8 W kg−1 in 1 M TEABF4/AN electrolyte. This work provides a new strategy for the synthesis of multiscale porous ACs for high-performance supercapacitors or other energy storage and conversion devices and is expected to be applied on other biomasses for large-scale production.

Plasma derived cross-linking of polymer surfaces is an established technique within industry. This study investigated how the utilization and proximity of an atmospheric plasma generating device affects the ultimate tensile strength and surface quality of 3D printed Acrylonitrile Butadiene Styrene. The study made use of a linear stage device to accurately modify the distance between parts and devices. We aimed to evaluate the potential of atmospheric plasma treatment to improve the mechanical performance of 3D printing systems. 3D printed samples were generated by a Tier Time UPBox Fused deposition modelling printer. Thirty ASTM D638 Type IV dog-bone samples were generated. They were grouped into 6 categories corresponding to varied heights from the generated plasma, namely 36 mm (Sample 1), 30 mm (Sample 2), 24 mm (Sample 3), 18 mm (Sample 4), 12 mm (Sample 5) as well as an unprocessed Benchmark Sample. Optimal ultimate tensile strength occurred at 24 mm being 19.01 MPa whilst the surface quality of the samples experienced little change.

In this letter, the optical properties of InAs (QDs)/GaInAsP on InP substrate grown by gas source molecular beam epitaxy are investigated. By measuring and analyzing the photoluminescence spectra of InAs (QDs)/GaInAsP/InP at different temperatures and excitation powers, the origin of each emission is verified. And it is found that, with the temperature increasing, the emission intensity of GaInAsP wetting layers decreases firstly (T

3D Printing additive manufacturing is a rapidly developing form of technology. Currently able to manipulate many polymers (both synthetic and organic) this technique is quickly becoming an integral part of biotechnological developments. This paper highlights the fundamentals of this technology namely the mechanisms employed in standard 3D printing it then introduces tissue engineering a field in which current versions of this technology have been employed as bioprinting. The limitations with respect to tissue engineering are discussed outlining the current technologies inability to produce nanofibre based structures common in tissue such as tendon cartilage and cornea. From this requirement for nanofibre production electrospinning is introduced as a potential pathway for future tissue engineering 3D printing technologies and finally the current combination of this technology with 3D Printing is discussed yielding current limitations in retaining required nano-resolutions.

This paper reviews current research on the design, processing and finite element analysis (FEA) of bone implants for the human body. The feasibility of producing carbon fibre composite implants, in particular knee and hip replacements which are common bone replacements by 3D printing, is discussed. The relationship between design and material requirements is elaborated.

The nature of fibre placement/manipulation in electrospinning has been recorded through the utilization of surface actuation and electrostatic manipulation. This study investigates the potential of a simplistic approach to fibre placement manipulation through the utilization of non-uniform non-conducting collecting surfaces. A solution of Nylon 6,6 and Formic acid was electrospun with an ES1a device and through the use of SEM analysis submicron and nanofibre alignment was identified. This study achieved the generation of actuation-less and electrode-less alignment reiterating current literatures rationale of alignment formation. The study noted limitations regarding the potential combination of mold/cavity and electrospinning based manufacturing. From this work future recommendations regarding surface modification have been derived.

Two different sizes of polydopamine-coated layered double hydroxides (D-LDHs) are incorporated into polycaprolactone-based polyurethane (PU) to enhance the mechanical and shape memory properties of the PU. The results show that D-LDH interacts strongly with hard segments and hence enhancing phase separation between hard and soft segments. It is found that the tensile moduli of the PU/D-LDH nanocomposites are much higher than that of neat PU at 60 oC. In comparison with neat PU, the nanocomposite with 2 wt% of small D-LDH exhibits a 60% increase in recovery stress while shape fixity and strain recovery ratio are also improved simultaneously. This is because at low filler loading, most small D-LDH nanosheets interact with hard domains and they are not large enough to connect neighbor hard domains. They can hence reinforce the hard domains without sacrificing the elasticity of the system. Two-dimensional X-ray diffraction studies indicate that most small D-LDH nanosheets are able to rotate back from aligned state to original random state in shape recovery process, justifying the improved strain recovery ratio. ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version

The spatial and temporal coherence of the fluorescence emission controlled by a quasi-two-dimensional hybrid photonic–plasmonic crystal structure covered with a thin fluorescent-molecular-doped dielectric film is investigated experimentally. A simple theoretical model to describe how a confined quasi-two-dimensional optical mode may induce coherent fluorescence emission is also presented. Concerning the spatial coherence, it is experimentally observed that the coherence area in the plane of the light source is in excess of 49 μm2, which results in enhanced directional fluorescence emission. Concerning temporal coherence, the obtained coherence time is 4 times longer than that of the normal fluorescence emission in vacuum. Moreover, a Young's double-slit interference experiment is performed to directly confirm the spatially coherent emission. This smoking gun proof of spatial coherence is reported here for the first time for the optical-mode-modified emission.

Carbon nanotube reinforced pyrolytic carbon/silicon nitride (CNT-PyC/Si 3 N 4 ) composite ceramics were fabricated through in-situ growth of CNTs in PyC–Si 3 N 4 ceramics by precursor infiltration and pyrolysis. CNTs were in-situ formed by the addition of nano-sized Ni into phenolic resin and Si 3 N 4 powder blend, and the content of CNTs increased with the increase of Ni content. Due to the formation of CNTs in the inter-particle pores of CNTs/PyC–Si 3 N 4 ceramic, the PyC wrapped Si 3 N 4 particles were bridged by CNTs, which led to the increase of electrical conductivity. Different from the previously reported PyC–Si 3 N 4 ceramics fabricated by chemical vapor infiltration (CVI), the PyC–Si 3 N 4 ceramics exhibited a shielding mechanism dominated by absorption. Compared to PyC–Si 3 N 4 ceramics prepared with same procedure, the shielding effectiveness of CNTs-PyC/Si 3 N 4 increased significantly with the formation of CNTs. With the increase of CNT content, the shielding effectiveness of CNTs/PyC–Si 3 N 4 ceram i cs increased from 25.5 to 43.6 dB, in which the absorption shielding effectiveness increased from 15 to 30 dB over the frequency range of 8.2–12.4 GHz.

Correction for ‘B, N-dual doped sisal-based multiscale porous carbon for high-rate supercapacitors’ by Heng Wu et al., RSC Adv., 2019, 9, 1476–1486.

Low-cost jute-based carbon fibers were fabricated by pre-oxidation and carbonization. The chemical, morphological and crystal structure of the jute fibers during pre-oxidation were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, elemental analysis, X-ray diffraction and scanning electron microscopy. Results show that the optimum pre-oxidation temperature range is from 250 to 340 °C. At 250 °C, significant oxidation occurs, the amount of C O functional groups reaches a maximum, the typical cellulose crystal structure disappears and a new aromatic structure appears. The C O functional groups are gradually lost while an aromatic structure steadily develops with a further increase of temperature from 250 to 340 °C. The tensile strength of the jute-based carbon fibers increases with increasing amount of the aromatic structure during pre-oxidation, rather than that of C O groups. The highest tensile strength of the carbon fibers is 200.4 ± 41.0 MPa. [New Carbon Materials 2013, 28(6): 448–453]

The mechanical properties and the life cycle assessment (LCA) of jute woven fabric composites and their hybrids are investigated. Jute woven fabric composites were sandwiched with glass woven composites with the epoxy matrix. The sandwiched composites were prepared using the resin infusion under flexible tooling method. The water absorption test was performed on jute woven composites and composite sandwiches. It shows that thin layers of glass woven composites in the composites sandwich decelerate water penetration to jute woven composites, which are the core materials. The water absorption process applied to jute woven composites and their sandwich was modeled using Fick’s second law. The glass woven composites at the outer surface of the sandwich can act as strong skins. The bending and impact (drop weight) properties of jute–glass woven composites are higher than those of jute woven composites. A commercial LCA software product was employed to evaluate the environmental impacts of manufacturing the jute woven composites and their hybrids. The manufacturing of jute–glass woven composites had more negative environmental impacts (global warming, ozone depletion, etc.) than that of jute fabric composites, because glass fibres are less environmental friendly than natural fibres.

Owing to the widespread presence of electromagnetic interferences, it is necessary to develop new materials with excellent high-temperature electromagnetic wave (EM) absorption properties. In the present work, ZnO is infiltrated into porous ZrSiO4 substrates to form ZnO/ZrSiO4 composite ceramics using sol-gel process. The doping of aluminum results in the improvement of electrical conductivity and the significant change in the morphology of ZnO. With the increase in environment temperature during measurement, the permittivity of the composite ceramics increases first and then decreases dramatically, which is attributed to the change in conductive loss. The electrical conductivity increases with increasing measurement temperature. However, the concentration of oxygen vacancies decreases under air atmosphere when the measurement temperature increases continuously, which results in the reduction in conductivity. Therefore, permittivities of the undoped and doped ceramics measured at 673 K are higher than the ones at the other temperatures. The composite ceramics maintain a relatively high EM absorption coefficient, low reflection coefficient (RC), and wide effective absorption bandwidth at environment temperatures up to 773 K. As a result, we conclude that the ZnO/ZrSiO4 composite ceramics exhibit a promising prospect as a kind of high-temperature EM absorbing material.

A (1→6)-β-D-glucan (WPLE-N-1) and two mannogalactoglucans (WPLE-N-2 and WPLE-N-3) were isolated from the basidiocarps of Lentinus edodes by hot water extraction, ethanol precipitation, anion exchange chromatography, and further purified by gel-permeation chromatography (GPC). Their structural features were investigated by high performance liquid chromatography (HPLC), high performance gel-permeation chromatography (HPGPC), methylation analysis, periodate oxidation-Smith degradation, Fourier transform-infrared (FT-IR) and NMR spectroscopy, including two-dimensional (2D) NMR. HPLC analysis revealed that WPLE-N-1 was mainly composed of glucose (92%) with small amount of galactose (3.9%) and mannose (4.1%), WPLE-N-2 and WPLE-N-3 contained mannose-galactose-glucose in the molar ratio of 10:27:63 and 5:12:83, respectively. GPC and HPGPC showed that WPLE-N-1, WPLE-N-2 and WPLE-N-3 are homogeneous fractions and their molecular weights were estimated to be 757.5 kDa, 20.9 kDa and 4.7 kDa, respectively. Chemical and spectroscopic studies indicated that WPLE-N-1 consisted of (1→6)-β-D-glucopyranosyl residues; while WPLE-N-2 and WPLE-N-3 were found to contain (1→6)-, (1→4)- and (1→3)-α-D-glucopyranosyl residues, (1→6)-α-D-galactopyranosyl residues, (1→3,6)- and (1→2,4)-α-D-mannopyranosyl residues and terminal residues of D-glucopyranosyl residues. On a preliminary bioactivity test, these three polysaccharides exhibited antitumor activity against Sarcoma S-180, Carcinoma HCT-116 and HT-29 in vitro. This finding suggests that mannogalactoglucan should be explored as potential antitumor agents and utilized as tumor cell growth inhibitors for food and pharmaceutical industries.

The paper presents the work on manufacturing and preliminary characterisation of fibre reinforced composite honeycomb structured composites by 3D printing. The capabilities and limitations of the processing are discussed. The work aims to compare the effectiveness of reinforcement using specimens of similar dimensions produced on the same machine and characterise them. Initially, tensile performance of unprinted fibre and printed fibre has been evaluated. Challenges associated with the testing of the printed specimens are addressed. Bend testing will follow to assess the performance as a composite structure to assess the interaction between fibre, matrix and core. Continuing work is planned to compare the effect of other parameters such as fill pattern and fill density to assess their effect on the composite.

Panax ginseng C. A. Meyer is a well-known plant medicine in the world. Ginseng polysaccharides mainly contain starch-like glucan and pectin. In this paper, a novel glucan WGPA-UH-N1 was purified from ginseng pectin by the treatment of de-esterification and endo-polygalacturonase, followed by the chromatographies on DEAE-Sepharose Fast Flow and Sephadex G-50 column. WGPA-UH-N1 has molecular weight about 17 kDa. WGPA-UH-N1 was determined to be a linear α-(1 → 6)-D-glucan without side chains by FT-IR, 13 C-NMR, 1 H-NMR, HMQC and HMBC spectra. It is the first time to isolate a linear α-(1 → 6)-D-glucan from Panax ginseng C. A. Meyer. Immunological activity assays showed that WGPA-UH-N1, although not effective on the phagocytosis of macrophage, could significantly induce lymphocyte proliferation without mitogenic stimuli at 1.0 mg/mL or with LPS at 0.5 mg/mL, also significantly increase NO production at the range of 0.1–1.0 mg/mL in a dose-dependent manner. The immunological activities of WGPA-UH-N1 are different from those of the β-(1 → 6)-D-glucan (BIWP2) isolated from the fruit bodies of Bulgaria Inquinans (Fries).

Voids and porosity are critical imperfections in fibre reinforced composite materials. The aim of this study is to assess the comparative accuracy and reliability of conventional and novel void characterisation techniques for analysing voids within carbon fibre reinforced composite (CFRC) laminates. While microscopy and Archimedes density measurements can only give results of limited accuracy and reliability, micro-computed tomography (micro-CT) analysis was found to have no significant inherent errors and is able to characterise the three-dimensional size, shape and distribution of voids in CFRC laminates. The accuracy of micro-CT was also verified by analysing artificial voids of a known size and shape disbursed throughout a CFRC laminate sample.

In this article, three bio-composites, i.e. flax, linen and bamboo fabric reinforced epoxy resin, were manufactured using a vacuum bagging technique. The influence of alkali treatment (with 5 wt% NaOH solution for 30 min) on tensile properties of flax, linen and bamboo single-strand yarns, surface morphology and mechanical properties (with respect to tensile and flexural properties) of the composites were investigated. It was found that the failure mechanism of single-strand fibres under tension consists of fibre breakage and slippage simultaneously. The alkali treatment had a negative effect on the tensile strength and modulus of the flax, linen and bamboo single-strand yarns. However, after the treatment, the tensile and flexural properties of all the composites increased, e.g. the tensile and flexural strength of the treated flax/epoxy composite increased 21.9% and 16.1%, compared to the untreated one. After the treatment in all the composites, the tensile fractured surfaces exhibited an improvement of fibre/epoxy interfacial adhesion.

The effects of cellulose nanowhiskers on the microstructure and thermal behaviour of electrospun poly (lactic acid) (PLA) nanofibres have been investigated in this study. The PLA/cellulose nanowhiskers composite nanofibres are successfully produced by electrospinning the mixtures of cellulose whiskers with PLA solution. The diameters of PLA and its composites are around 300 nm. The scanning electron micrographs show that the cellulose nanowhiskers do not protrude out of the outer surfaces of PLA nanofibres. The existence of cellulose nanowhiskers in the electrospun PLA matrix nanofibres, and the microstructural evolution are investigated by using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) analysis shows the formation trend of PLA α crystal with the addition of cellulose nanowhiskers. The electrospun PLA and PLA/cellulose nanowhiskers composites reveal very low crystallinity due to the rapid solvent evaporation and relatively slow crystallisation kinetics character of PLA. The electrospun nanofibres show particularly different thermal behaviour from that of the solution cast films. The nanofibres of pure PLA and PLA/cellulose nanowhiskers experience two consecutively overlapping crystallisation processes. The cellulose nanowhiskers act as heterogeneous sites for nucleation of PLA by decreasing the cold crystallisation onset temperature. The incorporation of cellulose nanowhiskers into PLA nanofibres is expected to improve mechanical properties and bring new functionalities to the electrospun matrix nanofibres.

This research addresses the influence of various processing parameters on the post cure quality of carbon fibre composites. Four processing parameters were investigated in the study, in terms of their impact on void content and overall compressive strength. The first parameter distinguishes between laminates cured in a vacuum oven and those cured in an autoclave under high positive pressure. The second parameter describes the impact on voids of differing fibre architectures, comparing a unidirectional fibre structure to that of woven cloth. Thirdly, the influence of compaction during manufacture is analysed and lastly, variation in cure temperature was tested to determine its effect on final laminate quality. The quality of the cured laminate samples was assessed from visual inspection, and in terms of compressive strength and void fraction calculated by Micro-CT X-ray Tomography. The results show that autoclave-cured samples feature significant quality improvements in terms of void fraction and compressive strength when compared to oven-cured samples. Unidirectional laminates incur higher sensitivity to void inclusion than cloth laminates due to the influence of fibre wrinkling. Compaction has no effect on laminate strength; it does however reduce variability in certain cases. Temperature affects different fibre structures in different ways, these being highly dependent on curing method. Finally, it was discerned that curing by autoclave was the dominant processing parameter. Thus, regardless of other manufacturing techniques, the autoclave samples featured almost zero voids and were consequently of the highest quality.

Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Com- posite films containing 2.5 and 5.0 wt% flax cellulose (FC) fibres were prepared by solution casting of mixtures of poly(lactic acid) (PLA) solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solu- tion cast pure PLA film, with thickness of around 160 μm, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

The purpose of this research was to develop a reinforcing material for polyethylene-based composite manufacture by rotational moulding. Wollastonite, sisal fibres and PE are premixed by blending and compounding with a single screw extruder and then granulated to particles with diameter about 0.5 mm prior to rotational moulding, for which the mixture is placed in a mould that is heated from the outside to 250 °C for a period of about 10 min. Aminosilane was used as a surface treatment for wollastonite. It was found that incorporating wollastonite microfibres improved the tensile properties of the system. When wollastonite fibres were coated with aminosilane, the impact strength and processability were enhanced greatly. Sisal fibres were added to improve the impact properties. Scanning electron microscopy revealed good adhesion between the coated fibre reinforcement and the polyethylene matrix at the fracture surface. The mechanism of this phenomenon is discussed.

This paper describes the development of a new processing technology for rotational moulding of wollastonite microfibre (WE) reinforced polyethylene (PE). Manufacturing wollastonite-polyethylene composites involved blending, compounding by extrusion, and granulating prior to rotational moulding. The properties of the resulting composites were characterised by tensile and impact strength measurements. The results show that tensile strength increases monotonically with the addition of wollastonite fibres, but impact strength is decreased. In addition, the processability is also decreased after adding more than 12 vol% WE because of increased viscosity. The effects of a coupling agent, maleated polyethylene (MAPE), on the mechanical performance and processability were also investigated. SEM analysis reveals good adhesion between the fibre reinforcements and polyethylene matrix at the fracture surface with the addition of MAPE. It is proposed that fillers with small particles with high aspect ratio (such as wollastonite) provide a large interfacial area between the filler and the polymer matrix, and may influence the mobility of the molecular chains.

The usefulness of rotational moulding (rotomoulding) as a polymer processing technique is often limited by the selection of polymers, which in most cases happens to be polyethylene (PE). In the present study, PE polyethylene was blended with wollastonite microfibres and maleated polyethylene (as a coupling agent) with the purpose of developing an improved material for rotational moulding. The incorporation of wollastonite fibres without any coupling agent improved the tensile strength, but showed a reduction in impact strength. As expected, the most significant enhancement due to wollastonite was in the tensile modulus.. The addition of a coupling agent improved both the impact strength and the processability, especially when wollastonite was coated with aminosilane. Scanning electron microscopy revealed good adhesion between the coated fibre reinforcement and the polyethylene matrix at the fracture surface.

The recycled aggregates were modified by sodium silicate, cement grout, cement mixed with superfine fly ash grout and polymer emulsion. The influence of the modified recycled aggregates to the mechanical properties of the concrete was studied. The results indicated that the recycled aggregates can reduce the compressive strength, split tensile strength and elasticity modulus. The modified process of the recycled aggregates can enhance the mechanical properties of the concrete. The early split tensile strength and elasticity modulus were preferably enhanced by sodium silicate. The cement grout and cement mixed with superfine fly ash grout can significantly improved the later mechanical properties. density and fraction passing 75μm sieve were 2650kg/m 3 and 1.3%, respectively.

Polyethylene-based and polypropylene-based composites, incorporating silica nanoparticles and geopolymers, were prepared by melt compounding. Scanning electron microscope (SEM) images indicate that the silica nanoparticles do not distribute uniformly as fine particles in the matrix, but are unevenly distributed as clusters. As a result, the tensile properties of those composites are inferior to those of the matrix polymer. A novel concept of in situ formation of a reinforcing phase has been investigated as a method of resolving that problem. The reinforcing elements are microcrystalline phases developed during melt processing of mixtures of geopolymer precursors with polyethylene or polypropylene. Preliminary tensile test data on injection moulded specimens show some improvement in mechanical properties of both geopolymer–polyethylene and geopolymer–polypropylene composites relative to the matrix polymers. Scanning electron micrographs clearly show the presence in the composites of a nanoscale aci...

In this study, argon and air-plasma treatments were used to modify the surface of woodfibres under suitable treatment parameters to improve the compatibility between woodfibres and polypropylene (PP). Woodfibres and PP fibres were blended together to form a random mat, which was then vacuum hot-pressed into a preimpregnated composite sheet. The tensile strength and tensile modulus of the composite sheet improved to some extent after the plasma treatment. The storage modulus in the dynamic mechanical properties of woodfibre-PP composites also showed improvement after the treatment. Furthermore, scanning electron microscopy analyses revealed the improved morphologies of the fractured surfaces of the composites. Surface characterisation, by X-ray photoelectron spectroscopy, showed increases in oxygen/carbon ratios of woodfibres after treatment.

In recent years, sisal fibres have become a promising reinforcement for composites because of their low cost, low density, high specific strength, high specific modulus, easy availability and renewability. However, the poor adhesion between the hydrophilic sisal fibre and the hydrophobic thermoplastic matrices has adversely affected the widespread use of these composites. In this study, argon and air-plasma treatments have been used to modify the fibre surfaces under suitable treatment parameters to improve the compatibility between sisal fibres and polypropylene (PP). Sisal fibres and PP fibres are blended together to form a random mat which is then vacuum hot-pressed into a preimpregnated composite sheet. Mechanical properties such as tensile strength and modulus, flexural strength and modulus, and the storage modulus of the composite sheets improve after the incorporation of plasma-treated fibres. Furthermore, scanning electron microscopy analyses reveal the increased surface roughness of sisal fibre. ...

Argon- and air-plasma treatments have been used to modify the surface of sisal fibres. The Taguchi method of experimental design with three factors and three levels is used to optimise the treatment parameters in relation to fibre strength. The effects of plasma treatment on interfacial bonding between sisal fibres and polypropylene are evaluated by means of a single fibre pull-out test. The optimum treatment parameters have been found to be the shortest plasma treatment time, medium power level and medium chamber pressure. Under optimal treatment, the interfacial shear strength of air-plasma treated fibres is higher than that of the argon-plasma treated fibres. Scanning electron microscopy analyses show that the overall roughness of the plasma treated fibre surface increases with treatment time. The Ar-plasma treated fibre surface reveals obvious corrugations whereas cracking is apparent on the air-plasma treated fibre surface.

Poly(lactide) (PLA) — flax fibers stereocomplex composites were prepared by casting commercial poly(L-lactide) (PLA) and flax-g-poly(D-lactide) (flax-g-PDLA), where flax-g-PDLA was synthesized via ring-opening polymerization. Successful surface grafting was revealed by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) studies. DSC results showed that stereocomplex crystallites formed between the PLA matrix and flax-g-PDLA, resulting in good fiber/PLA interfacial adhesion.