198,198 research outputs found
Rosin-Modified Polyurethane Elastomers with Room-Temperature Self-Healing Ability, High Strength, and Recyclability Based on Oxime Dynamic Bonds
No full textRosin, with a rigid hydrogenated phenanthrene ring, is
a widely
available biomass, but its high-value utilization needs to be enhanced.
Inspired by sustainable development strategies, the design of polymer
elastomers with a room-temperature self-healing capability has been
a hot focus topic. However, designing elastomers that combine the
conflicting properties of high mechanical performance and room-temperature
self-healing is a significant challenge. The hydrogenated phenanthrene
ring of rosin provides a superior solution to this problem. In this
work, the polyurethane elastomer (BPU-X% AP) based
on rosin-hydrogenated phenanthrene ring structure, dynamic oxime,
and hydrogen bonding was reported. The BPU-X% AP
exhibits high tensile strength (37.8 MPa), and good toughness (126.9
MJ m–3). Due to the rosin structure that promotes
the movement of the elastomer chain segments, the elastomers have
fast room-temperature self-healing and recyclability. Benefiting from
their excellent mechanical strength and self-healing properties, BPU-X% AP as adhesives exhibits a strong lap shear strength
of 5.5 MPa, and they can be used as hot melt binders. Corresponding
to the cycling of the elastomer, the adhesive strength of BPU-10%
AP remains almost the same after three cycles of adhesion to the iron
and aluminum plates. This work provides a viable approach for the
preparation of high-performance biomodified polyurethanes
Study of biodegradation and biocompatibility of PEGylated rosin derivatives
No full text PEGylated rosin derivatives are improved in series ester-adduct derivatives of rosin. The aim of this study was to assess biodegradation and biocompatibility of PEGylated rosin derivatives. Study employed two different PEGylated rosin derivatives, namely, D1 and D2, with constant weight of rosin and increasing amounts of polyethylene glycol 400. PEGylated rosin derivatives were synthesized and tailored into spherical beads and disks with smooth surface for use. In vitro degradation was studied at pH 4.0, 7.4, and 10 for 60 days. In vivo study was performed in Wistar rats using poly(d,l-lactide- co-glycolide) (50:50) as a control. Post 3, 7, 14, and 21 days of implantation, PEGylated rosin derivatives disks were retrieved and evaluated for weight loss, molecular weight decline, morphology, and tissue response. D1 and D2 beads showed 21.68% and 32.37% weight loss, respectively, at pH 7.4 post 60 days. Degradation was increased substantially with increase in pH of medium. Degradation of disks was markedly slower than that of beads. In vivo degradation of PEGylated rosin derivative disks was faster than in vitro. Post 60 days of implantation, weight loss of D1 and D2 disk was 7.57% and 11.84%, whereas molecular weight was declined by about 19% and 26%, respectively. Owing to higher amounts of polyethylene glycol 400, in vitro and in vivo degradation of D2 was faster than D1. Poly(d,l-lactide- co-glycolide) as well as PEGylated rosin derivative implants evoked mild inflammatory responses characterized by few macrophages and absence of exudation at tissue–disk interface. The cellular density in tissue surrounding PEGylated rosin derivative disks increased initially with time up to 7 days and decreased eventually at the end of 21 days. The trend was similar for poly(d,l-lactide- co-glycolide) implants. Increase in polyethylene glycol 400 improved biodegradation and biocompatibility of PEGylated rosin derivatives. Results revealed that PEGylated rosin derivatives degrade slowly in vivo over a period of time, possess fair biocompatibility, and thus are promising biomaterial for drug delivery applications. </jats:p
Comparison of Rosin and Propolis Antimicrobials in Cellulose Acetate Fibers Against Staphylococcus aureus
No full textThe quantitative difference in the antibacterial response was measured for pine rosin and propolis against Staphylococcus aureus ATCC 12598. The activity was studied for fibrous networks that form entirely bio-based cellulose-acetate (CA) materials. The analysis considers the effects of bacterial input, additive dosage, solvent type, variation in preparation, as well as the effect of storage time. Based on the results, the electrospun network structure is dependent on the solvent and the concentration of rosin and propolis. Both rosin and propolis improved the cellulose acetate solution processability, yet they formed beads at high concentrations. Rosin and propolis created strong antibacterial properties when these material systems were immersed in the liquid for 24 h at room temperature. The response remained visible for a minimum of two months. The electrospun networks of water and DMAc solvent systems with 1 to 5 wt% rosin content were clearly more efficient (i.e., decrease of 4 to 6 logs in colony forming units per mL) than the propolis networks, even after two months. This efficiency is likely due to the high content of abietic acids present in the rosin, which is based on the Fourier transform infrared spectra. The results of the additional analysis and cell cultivation with dermal fibroblast cells indicated an impairing effect on skin tissue by the rosin at a 1 wt% concentration compared to the pure CA fibers.Peer reviewe
Antibacterial polymer fibres by rosin compounding and melt-spinning
No full textThe antibacterial features of natural pine/spruce rosin are well established, yet the functionality in various thermoplastics has not been surveyed. This work focuses on the processing of industrial grade purified rosin mixed with polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyamide (PA) and corn starch based biopolymer (CS). Homopolymer masterbatches were extrusion-compounded and melt-spun to form fibres for a wide range of products, such as filters, reinforcements, clothing and medical textiles. Due to the versatile chemical structure of rosin, it was observed compatible with all the selected polymers. In general, the rosin-blended systems were shear-thinning in a molten condition. The doped fibres spun of PE and PP indicated adequate melt-spinning capability and proper mechanical properties in terms of ultimate strength and Young's modulus. The antibacterial response was found dependent on the selected polymer. Especially PE with a 10 wt% rosin content showed significant antibacterial effects against Escherichia coli DH5α and Staphylococcus aureus ATCC 12598 when analysed in the Ringer's solution for 24 h.Peer reviewe
Synthesis and properties of interaction product of rosin and diethylenetriamine
No full textAmides of rosin resin acids are a promising material for use in the technology of paper and cardboard in order to increase its strength characteristics. Therefore product of rosin resin acids interaction with diethylenetriamine arouses interest. The influence of temperature and duration of the process of interaction of rosin resin acids with diethylenetriamine on the acid number of the product are examined in this article. Melting point of the received rosin amides was defined. The thermal stability of the reaction product of abietic acid with diethylenetriamine was studied. It was proved that this product contains the appropriate functional groups using IRspectroscopy
Synthesis and properties of interaction product of rosin and diethylenetriamine
No full textAmides of rosin resin acids are a promising material for use in the technology of paper and cardboard in order to increase its strength characteristics. Therefore product of rosin resin acids interaction with diethylenetriamine arouses interest. The influence of temperature and duration of the process of interaction of rosin resin acids with diethylenetriamine on the acid number of the product are examined in this article. Melting point of the received rosin amides was defined. The thermal stability of the reaction product of abietic acid with diethylenetriamine was studied. It was proved that this product contains the appropriate functional groups using Irspectroscopy
eWOM and growth strategies for the tourism industry in maritime museum networks. The case of the ARCA Adriatica tourist product
No full textMuseum networks are proliferating in the Mediterranean area showing new forms of collaboration between public and private institutions. Museums and heritage conservation play a fundamental role in tourism development. The purpose of the present working paper is to provide an analysis of the museum network experience in order to define a set of useful and viable marketing strategies to be adopted by the museum management with respect to the relative tourist context. The case of the Arca Adriatica maritime museum network - a network of eight maritime museums representing the core asset of an elaborated tourist product - has been analyzed and considered particularly relevant and of peculiar interest. After the analysis of the museum network and its most important related points of interest, managerial recommendations within strategic and tactical perspectives are hence presented
Food utopias: hoping the future of agriculture
No full textWhen one walks the aisles of a typical America, Australian or German wealthy supermarket, the shelves are teeming with food-- cans, bags, packages, fruits, vegetables, freezers and refrigerators teeming with safely sealed meat packages, deli counters with gruyere and potato casserole, edamame salads, swimming lobsters-- a literal cornucopia of food. For many in the developed and wealthy classes of the world, this vision of access to any and all kinds of varieties of food is the norm. In contrast to our book Food Systems Failure (2011), which chronicled the most recent international food crises prompted by high staple crop prices, Food Utopias aims to highlight the various stories that food tells us about ourselves, both critical and hope-filled
The study of influence of nitrogen containing rosin adducts derivatives on technical properties of elastomeric compounds
No full textThe following substances were used as additives: maleated rosin modified with oleic acid, containing maleopimaric acid ( ≈50%) which did not react with maleic anhydride rosin acids; rosin-itaconic ac-id adduct, containing up to ≈50% of citraconopimaric acid as a mixture of two isomers; octylimide of rosin-itaconic acid adduct; imide of maleated rosin and aniline, containing up to ≈50% of N-phenylimide of maleopimaric acid; imidoamide of maleated rosin and aniline, containing maleo-pimaric acid anilide N-phenylimide; imidoamide of maleated rosin and p-anisidine, containing maleopimaric acid p-methoxyphenylamide N-( p-methoxyphenyl)imide. Their uses as processing aids in rubber compounds based on synthetic isoprene rubber are considered. Processing parameters, such as Mooney viscosity, scorch resistance, kinetic characteristics of vulcanization of the rubber mixtures with nitrogen adducts of rosin are investigated
Synthesis and Properties of Maleated Rosin Acid-polyethyleneglycol Ester
No full text以松香、顺丁烯二酸酐、聚乙二醇为原料合成了标题化合物。研究了合成条件对产物酸值的影响,确定最佳合成条件为：0.5%对甲苯磺酸为催化剂、PEG分子量为200、投料比m（马来松香）∶m（PEG200）=1∶2、180℃下反应24 h。采用红外光谱和凝胶渗透色谱对其结构进行了初步表征,并测定了聚合物的溶解性、表面张力、乳化力。结果表明,该聚合物能溶于大多数极性和非极性溶剂中,聚马来松香PEG酯溶液临界胶束浓度（CMC）值为12 g/L,γCMC为37 m N/m,对油脂有良好的乳化性能。The maleated rosin acid-polyethylene glycol ester was synthetized with rosin, cis-maleic anhydride and polyethylene glycol. The effect of synthesis conditions on the acid value of polymer was investigated. The suitable conditions for polyester were as following：reaction temperature was 180 ℃ ,reaction time was about 24 h,the molar ratio of maleated rosin to polyethylene gly- col 200 was 1：1.2 - 1：1.5 with 0.5% toluene-p-sulfonic acid as catalyst. The structure of polymers was characterized by IR and GPC. The solubility, surface tension and emulsifying power of maleated rosin acid-polyethyleneglycol ester were measured. The results showed that the polymer could dissolve in most polar and non polar solvents,the critical micelle concentration of the poly- mer is 12 g/L and the surface tension is 37 mN/m. The maleated rosin acid-polyethyleneglycol ester had good emulsifying proper- ties to grease.广西自然科学基金资助项目(2013jj BA20043);广西教育厅科学技术研究资助项目(2013YB077);广西民族大学科研基金资助项目(2011MDQN034
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