This paper describes preparation and properties of green nanocomposites from renewable resources. The nanocomposites were synthesized by an acid-catalyzed curing of epoxidized natural oils in the presence of silane coupling agents. The resulting nanocomposites were transparent and highly glossy. Their hardness and Young's modulus of the nanocomposite coatings improved, as compared with those only from the epoxidized natural oils. Dynamic viscoelasticity analysis and TEM observation showed the homogeneous structure of the nanocomposites. The properties of the nanocomposites were strongly affected by the structure and feed ratio of the monomers. 相似文献
A new class of energetic biopolymers, which contain nitrate ester (O-NO2) and nitramine (N-NO2) as explosophoric groups, was successfully synthesized by surface modification of renewable pristine cellulose (PC) and microcrystalline cellulose (MCC) via epichlorohydrin-mediated amination followed by nitration process to produce new promising energetic aminated and nitrated cellulose and microcrystalline cellulose (APCN and AMCCN). Their structural, thermal, crystallinity and morphological features were examined and compared to those of the common cellulose nitrate. Furthermore, their energetic performances were evaluated by EXPLO5 V6.04 software. Experimental results confirm the successful chemical functionalization process to develop insensitive APCN and AMCCN with outstanding features such as nitrogen content of 15.01% and 15.39%, density of 1.692 g/cm3 and 1.708 g/cm3, and detonation velocity of 7526 m/s and 7752 m/s, respectively, which are significantly higher than those of the nitrated unmodified cellulosic biopolymers. The present investigation provides a suitable pathway to design new insensitive and energy-rich dense cellulosic biopolymers for potential application in high-performance solid propellants and composite explosives.
<正>Fossil fuels have sustained the prosperity of human civilization for centuries since the invention of internal combustion engine during the first industrial revolution.However,several drawbacks also come along with the wide-spread adoption of fossil fuels,namely,energy shortage,environmental pollution,global warming,and so on.It is therefore highly desirable to conduct 相似文献
The biodegradability, morphology, and mechanical properties of composite materials consisting of acrylic acid-grafted poly(butylene succinate adipate) (PBSA-g-AA) and agricultural residues (rice husk, RH) were evaluated. Composites containing acrylic acid-grafted PBSA (PBSA-g-AA/RH) exhibited noticeably superior mechanical properties compared with those of PBSA/RH due to greater compatibility with RH. The dispersion of RH in the PBSA-g-AA matrix was highly homogeneous as a result of ester formation, and the consequent creation of branched and cross-linked macromolecules, between the carboxyl groups of PBSA-g-AA and hydroxyl groups in RH. Each composite was subject to biodegradation tests in an Azospirillum brasilense BCRC 12270 liquid culture medium. The bacterium completely degraded both the PBSA and the PBSA-g-AA/RH composite films. Morphological observations indicated severe disruption of the film structure after 20-40 days of incubation. The PBSA-g-AA/RH (20 wt%) films were not only more biodegradable than those made of PBSA but also exhibited lower molecular weight and intrinsic viscosity, implying a strong connection between these characteristics and biodegradability. 相似文献
AbstractA series of lignin-based waterborne polyurethanes (ELWPUs) are prepared using epichlorohydrin-modified lignin (ELG) as the biobased component. The effect of ELG dosage on the performance of the dispersions was studied by particle sizing. The morphology, crystallinity, thermal behavior, water resistance and mechanical properties of the films were investigated as well. The results show that the particle size of ELWPU dispersions increased with the addition of ELG. Furthermore, the ELWPU exhibited noticeable thermal stability, desired mechanical properties and water resistance as the tensile strength of ELWPU film containing 0.25?wt% ELG increased to 40.6?MPa from 15.2?MPa and the water absorption rate decreased from 20.1 to 12.4% compared to the non-modified waterborne polyurethane. The ELG played an important role in improving the properties of the biomass-based materials. 相似文献
Readily recyclable biobased plastics were designed and synthesized utilizing the thermally reversible DA reaction. Furyl-telechelic poly(butylene succinate) prepolymers (PBSF(2)) were extended with bis- and tris-maleimide linkers (M(2) and M(3)) by the DA reaction in the bulk state to produce linear and network polymers, respectively. The DA reaction was able to proceed at 25-80 degrees C, at which crystalline domains of PBSF(2) were present. In the linear polymer system, the molecular weight in the reaction equilibrium was dependent on the chain length of the prepolymer, but almost independent of the reaction temperature. The cycle of DA and retro-DA reactions was repeatable with no prepolymer deterioration. 相似文献
In order to develop biomedical materials we synthesized various polymers. In this study, gelatin, synthetic poly(amino acid), chitin and chitosan were chosen as the basic materials of artificial skin, polyurethane, amino acid, silicone and N-vinyl-2-pyrrolidone were chosen as the basic materials of blood-compatible materials. 相似文献
Carbon modifications (anode matrices) were produced from renewable vegetable raw materials, agricultural crop waste, by pyrolysis in a quartz reactor without access of oxygen at 900°C, as well as by mechanical synthesis, and their characteristics were examined. 相似文献
The utilization of plant oil renewable resources as raw materials for monomers and polymers is discussed and reviewed. In an age of increasing oil prices, global warming and other environmental problems (e.g. waste) the change from fossil feedstock to renewable resources can considerably contribute to a sustainable development in the future. Especially plant derived fats and oils bear a large potential for the substitution of currently used petrochemicals, since monomers, fine chemicals and polymers can be derived from these resources in a straightforward fashion. The synthesis of monomers as well as polymers from plant fats and oils has already found some industrial application and recent developments in this field offer promising new opportunities, as is shown within this contribution. (138 references.) 相似文献
The objective of this work is to study the removal of malachite green (MG) from water by adsorbents obtained from pyrolysis
of two paper industry waste materials: one de-inking paper sludge (HP) and one organic sludge from virgin pulp mill (RT).
Both adsorbents showed elevated MG removal. Maximum adsorption Q0 obtained by Langmuir equation was higher for the adsorbent from HP (HP-3, 982 mg/g) than RT (RT-3, 435 mg/g). However, KL (Langmuir) and 1/n (Freundlich) indicated that affinity and intensity of adsorption is higher for the adsorbents from RT. Thermal analysis (TG,
DTG and DTA) of adsorbents before and after MG removal was performed in N2 atmosphere. 相似文献
Summary Sepabeads FP series with a variety of anion-exhanger type functional groups have been examined as largescale chromatographic
separation media for proteins. The adsorption-desorption behavior of proteins has been found to be dependent mainly on the
type and partly on the content of the attached amino ligands. The effect of the attached groups are discussed using batch
measurement data. It has been found that the existence of ethanol residue on the nitrogen atom incrases the hydrophilic nature
of quaternary ammonium type packings and thus gives a higher protein adsorption capacity. Among weakly basic type anionexchangers,
polyethyleneimine-modified packings showed very large protein capacities.
Presented at HPLC '87, Amsterdam, 1987. 相似文献
Developing thermosets derived from renewable sources is of great importance. In this work, a fully bio-based benzoxazine monomer, 3,6-bis((3-(furan-2-ylmethyl)-3,4-dihydro-2H-benzo[e][1,3]oxazin-6-yl)methyl)piperazine-2,5-dione (TCDPF), is conveniently synthesized from L-tyrosine cyclic dipeptide (TCDP), furfurylamine and paraformaldehyde. The chemical structure of TCDPF is confirmed by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy (FT-IR) techniques. The curing behavior of TCDPF is investigated by differential scanning calorimetry and in situ FT-IR techniques. After temperature-programmed curing, the thermomechanical property and thermal stability of the resulting TCDPF polymer (PTCDPF) are evaluated by dynamic mechanical analysis and thermogravimetric analysis techniques, respectively. It is found that PTCDPF have excellent comprehensive performance such as high glass transition temperature (Tg = 322 °C), high thermal degradation temperature (T5% = 342 °C, T10% = 395 °C in N2 atmosphere), and high char yield (CY = 51.3% at 800 °C in N2 atmosphere). The results demonstrate that L-tyrosine is a promising bio-based raw material for preparing high performance polybenzoxazines. 相似文献
Many micro-structural aspects of advanced materials and the incidence on the physical properties have been elucidated by Raman micro-spectroscopy. The potential of this technique is demonstrated with new materials interesting in both academic and industrial developments: new carbons and diamonds, superconductors, semiconductors, superhards. 相似文献