Research on various factors influencing the moisture absorption property of sodium polyacrylate

Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.

Protein partitioning in poly(ethylene glycol)/sodium polyacrylate aqueous two-phase systems

The partition of hemoglobin, lysozyme and glucose-6-phospate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na2SO4, pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation of hemoglobin occurs, high recovery values are obtained particularly for lysozyme and G6PDH. The partitioning forces are dominated by the hydrophobic and electrochemical (salt) effects, since the positively charged lysozyme and negatively charged G6PDH partitions to the non-charged PEG and the strongly negatively charged polyacrylate enriched phase, respectively. (c) 2007 Elsevier B.V. All rights reserved.

Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

聚丙烯酸钠对黄土坡面产流产沙的影响研究

通过野外模拟降雨试验,研究了施用SP对黄土坡面产流、产沙的影响,并对实验数据进行数学模拟,建立了SP施用量与产流、产沙强度间的关系模型。结果表明:SP施用量与产流时间、平均产流强度呈二次函数相关关系,与产沙强度呈线性负相关关系。SP用量在0~2.42 g/m2之间时,能够延缓坡面产流,用量为1.21 g/m2时延缓产流效果最明显;用量介于0~3.31 g/m2之间时,能够增加土壤入渗,减少坡面产流量,用量1.65 g/m2的增渗减流效果最佳;施用SP后,能够减少坡面输沙强度,且用量越大,减沙效果越明显。SP可影响坡面产流过程,用量1.8 g/m2时,能够减小产流初期径流强度增幅,用量为3.6 g/m2时,其产流过程线与对照极接近,而施用量增加到5.4 g/m2时,产流强度明显增大。SP对坡面产沙过程的影响表现为:随施用量增大,产沙强度峰值呈逐步减小的变化趋势。

两种高分子保水材料对盆栽甘蓝影响研究

采用盆栽试验,研究了两种高分子化合物聚丙烯酸钠(sodium polyacrylate,SP)与聚丙烯酰胺(Polyacrylamide,PAM)对甘蓝生长的影响。结果表明:在土壤中施入2/1000的两种高分子材料均能抑制土壤蒸发,砂土、粘土蒸发强度分别较对照降低35.5%、22.8%;甘蓝叶绿素受两种材料的影响不显著,受肥料影响较大;两种高分子材料施入土壤中增加了甘蓝产量、降低了根冠比,地上、地下生物量砂土较对照分别增加了61.1%、16.1%,粘土分别增加了55.2%、28.7%,根冠比砂土较对照平均降低了26.9%,粘土降低16%;PAM与SP使砂土容重较对照降低了13.9%,而粘土仅降低了4.1%;单施高分子处理水分利用效率平均较对照增加59.1%,与肥料混合使用时增加77.1%。总体来看,PAM与SP作用效果相近。

聚丙烯酸钠对3种土壤持水能力及作物产量的影响

在离心机模拟不同水吸力条件下,研究了聚丙烯酸钠(sodium polyacrylate记作SP)5种使用浓度(占干土质量0,0.01%,0.08%,0.2%与1%)对3种土壤(砂土、壤土、黏土)持水能力的影响;采用大田试验研究了地表撒施2 g/m2SP对冬小麦与下季玉米产量及WUE影响。结果表明:3种土壤在0.01 MPa至1.5 MPa水吸力下的持水能力随着SP用量的增加而增加,砂土的作用效果较壤土、黏土更显著;3种土壤适宜浓度为0.08%~0.2%,最佳用量为0.2%,此用量条件下砂土、壤土、黏土的最大毛管持水量分别较对照增加了138.61%,7.22%,62.70%;不灌水条件下,SP处理较不施用SP冬小麦增产4%,WUE增加5.7%,灌浆期灌水28.5 mm条件下SP处理较不施用SP增产1%,WUE降低1%;SP处理的玉米产量较对照降低0.5%,WUE提高3%,效果明显低于对冬小麦效果。

2种高分子保水材料对土壤持水能力的影响

采用离心机法,研究聚丙烯酸钠与聚丙烯酰胺2种高分子化合物在5种使用浓度(占干土质量0、0.01%、0.08%、0.2%与1%)的条件下对3种土壤(砂土、壤土、黏土)持水能力的影响。结果表明:3种土壤在0.01~1.5MPa水吸力时,持水能力随着2种高分子材料用量的增加而增加,砂土的作用效果较壤土、黏土更显著;2种高分子材料与土壤质量比控制在8/10000~2/1000范围内其作用效果较好,该用量条件下高分子吸持水分平均可释放83.7%供植物吸收利用。2种高分子材料对土壤持水能力的作用效果基本相同。

土壤中施用聚丙烯酸钠保水剂对冬小麦生长及产量影响

聚丙烯酸钠因其特殊的保水性能受到广泛重视,但是其研究仍多限于实验室模拟研究。为了促进其在农业生产中的应用与推广,该文采用大田试验,研究了聚丙烯酸钠对冬小麦生长、产量及水分利用效率(WUE)的影响。结果表明施入聚丙烯酸钠能够促进小麦生长,提高小麦叶绿素含量,提高小麦产量与WUE。采用沟施5.5 m3/hm2的1/2000聚丙烯酸钠水溶液,能够使小麦较对照增产2.9%,WUE增加3.52 kg/(hm2.mm);与肥料混合使用时,增产效果更加显著,可增产10.14%,WUE增加4.38 kg/(hm2.mm)。

Influência da granulometria e de aditivos no comportamento reológico do rejeito de lavagem da bauxita

Na mineração da bauxita no município de Paragominas-PA, são descartados no processo de beneficiamento rejeitos com teor de sólido de 33,5 % e granulometria muito fina com D₅₀ abaixo de 5 μm. Esses fatores contribuem para que esta suspensão formada basicamente por silico aluminatos, com elevada concentração de argila caulinita, apresente alta viscosidade e alta tensão inicial de escoamento. Foi realizada análise granulométrica e determinadas as composições químicas e mineralógicas do material. A análise granulométrica foi feita por peneiramento a úmido e as frações finas foram determinadas pela técnica da difração a laser. A determinação da composição química foi feita por Espectrometria de Fluorescência de Raios-X, obtendo-se considerável teor de alumina aproveitável, 21, 28%. A composição mineralógica foi determinada por Difração de Raios-X (DRX), obtendo-se gibsita, hematita, quartzo e caulinita. Realizou-se a determinação dos fatores de atrito da polpa, utilizando equação para fluidos que seguem o modelo de Herschel-Bulkley e utilizando as correlações de Dodge e Metzner. Utilizou-se o viscosímetro VT550, com sensor tipo cilindros coaxiais SV1, para realizar testes de defloculação e floculação utilizando diferentes aditivos reológicos. Os aditivos utilizados foram: hexametafosfato de sódio, hidroxamato, sulfato de alumínio, poliacrilato de sódio e poliacrilamida 25% aniônica. A programação foi taxa de cisalhamento de 100 s^-1, tempo de 20s e temperatura de 32ºC. Os defloculantes podem ser utilizados para melhorar o processo de bombeamento e os floculantes podem ser utilizados como auxiliadores no processo de sedimentação nos espessadores, auxiliando no processo de separação sólido-líquido. Foram realizadas ainda, análises de viscosidade em polpas com diferentes pH e em amostras passante a 400# Tyler, com o objetivo de avaliar se a granulometria e o pH influenciavam no comportamento dos aditivos. Pelo estudo observou-se que a granulometria e o pH influenciam no comportamento dos aditivos, pois quanto menor a granulometria mais eficiente é a atuação do aditivo e o seu comportamento como floculante ou defloculante está condicionado ao ajuste do pH.

Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two-phase polymer systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A stable liquid-liquid extraction system for clavulanic acid using polymer-based aqueous two-phase systems

The partitioning of Clavulanic Acid (CA) in a novel inexpensive and stable aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The aqueous two-phase systems are formed by mixing both polymers with a salt (NaCl or Na2SO4) and an aqueous solution of CA. The stability of CA on the presence of both polymers was investigated and it was observed that these polymers do not degrade the biomolecule. The effect of PEG-molecular size, polymer concentrations on the commercial CA partitioning has been studied, at 25 degrees C. The data showed that commercial CA was preferentially partitioned for the PEG-rich phase with a partition coefficient (K-CA) between 1 and 12 in the PEG/NaPA aqueous two phase systems supplemented with NaCl and Na2SO4. The partition to the PEG phase was increased in the systems with high polymer concentrations. Furthermore, Na2SO4 caused higher CA preference for the PEG-phase than NaCl. The systems having a composition with 10 wt.% of PEG4000, 20 wt.% of NaPA8000 and 6 wt.% of Na2SO4 were selected as the optimal ones in terms of recovery of CA from fermented broth of Streptomyces clavuligerus. The partitioning results (K-CA = 9.15 +/- 1.06) are competitive with commercial extraction methods of CA (K-CA = 11.91 +/- 2.08) which emphasizes that the system PEG/NaPA/Na2SO4 can be used as a new process to CA purification/concentration from fermented broth. (C) 2012 Elsevier B.V. All rights reserved.

Desenvolvimento de emulsões o/a contendo extrato glicólico de açai e avaliação da atividade fotoprotetora

Sunscreen use is the most common photoprotection alternative used by the population, and so these products should offer improved protection with broad - spectrum, UVA and UVB protection . Vegetal substances have recently been considered as resources for sunscreen formulations due to their UV spectrum absorption and antioxidant properties. The Euterpe oleracea Mart., popularly known as açai, in its che mical composition contain polyphenols compounds, such as anthocyanins and flavonoids , to which antioxidant properties have been attributed . The aim of this work was to develop O/W sunscreens emulsions con taining açai glycolic extract ( AGE) and to evaluate both their physical stability , safety and photoprotective efficacy. The safety of the extract was evaluated by in vitro phototoxicity and cytotoxicity tests. Emulsions containing AGE and sunscreens were formulated using different types and concentrations o f polymeric surfactant (Acrylates/C 10 - 30 Alkyl Acrylate Crosspolymer and Sodium Polyacrylate). The influence of two rheology modifiers (Polyacrylamide (and) C13 - 14/Isoparaffin (and) Laureth - 7 and Carbomer) on the stability was also investigated. Physical stability was evaluated by preliminary and accelerated studies. The macroscopic analyses, pH value and electrical conductivity determinations and rheological behavior were evaluated at different time intervals . The in vivo Sun Protect Factor ( SPF ) was determined according to the International Sun Protection Factor Test Method – 2006 and UVA Protection Factor (FPUVA), wavelength critical and reason SPF/FPUVA were performed according to the method Colipa 2011. The extract did not present cytotoxic ity and phototoxic ity . The stable emulsion containing 5% glycolic extract of açai and 1.0% of sodium poliyacrylate showed pseudoplastic and thixotropic behavior . The sunscreen emulsion containing açai glycolic extract showed a SPF 25.3 and PF - UVA = 14.97. Whe n açai glycolic extract was added in the emulsion sunscreen, no significant increase in the in vivo SPF and FPUVA values were observed. This emulsion showed 1.69 of the SPF/PF - UVA ratio and a critical wavelength value of 378 nm, so may therefore be conside red a sunscreen with UVA and UVB protection.

Obtenção de extratos da Opuntia fícus-indica L. Mill e suas aplicações em formulações cosméticas: avaliação in vivo do sensorial e da eficácia hidratante

Opuntia fícus - indica (L.) Mill is a cactacea presents in the Caatinga ecosystem and shows in its chemical c omposition flavonoids, galacturonic acid and sugars. Different hydroglicolic (EHG001 and EHG002) and hydroethanolic subsequently lyophilized (EHE001 and EHE002) extracts were developed. The EHE002 had his preliminary phytochemical composition investigated by thin layer chromatography (TLC) and we observed the predominance of flavonoids. Different formulations were prepared as emulsions with Sodium Polyacrylate (and) Hydrogenated Polydecene (and) Trideceth - 6 (Rapithix® A60), and Polyacrylamide (and) C13 - 14 I soparaffin (and) Laureth - 7 (Sepigel® 305), and gel with Sodium Polyacrylate (Rapithix® A100). The sensorial evaluation was conducted by check - all - that - apply method. There were no significant differences between the scores assigned to the formulations, howe ver, we noted a preference for those formulated with 1,5% of Rapithix® A100 and 3,0% of Sepigel® 305. These and the formulation with 3% Rapithix® A60 were tested for preliminary and accelerated stability. In accelerated stability study, samples were stored at different temperatures for 90 days. Organoleptic characteristics, the pH values and rheological behavior were assessed. T he emulsions formulated with 3,0% of Sepigel® 305 and 1,5% of Rapithix® A60 w ere stable with pseudoplastic and thixotropic behavior . The moisturizing clinical efficacy of the emulsions containing 3,0% of Sepigel® 305 containing 1 and 3% of EHG001 was performed using the capacitance method (Corneometer®) and transepidermal water lost – TEWL evaluation ( Tewameter®). The results showed t hat the formulation with 3% of EHG001 increased the skin moisturizing against the vehicle and the extractor solvent formulation after five hours. The formulations containing 1 and 3% of EHG001 increased skin barrier effect by reducing transepidermal water loss up to four hours after application.

Encapsulamento de solventes em nanotubos de haloisita para promoção de auto-reparo em polímeros

Micro cracking during service is a critical problem in polymer structures and polymer composite materials. Self-healing materials are able to repair micro cracks, thus their preventing propagation and catastrophic failure of structural components. One of the self-healing approaches presented in the literature involves the use of solvents which react with the polymer. The objective of this research is to investigate a procedure to encapsulate solvents in halloysite nanotubes to promote self-healing ability in epoxy. Healing is triggered by crack propagation through embedded nanotubes in the polymer, which then release the liquid sovent into the crack plane. Two solvents were considered in this work: dimethylsulfoxide (DMSO) and nitrobenzene. The nanotubes were coated using the layer-by-layer technique of oppositely charged polyelectrolytes: cetyltrimethylammonium bromide (CTAB) and sodium polyacrylate. Solvent encapsulation was verified by X-ray diffraction (XRD), Fourier transform infrared (FTIR), analysis thermogravimetry (TGA), adsorption and desorption of nitrogen and scanning electron microscopy (SEM). The introduction of the solvent DMSO into the cavity of the nanotubes was confirmed by the techniques employed. However, was not verified with nitrobenzene only promoted clay aggregation. The results suggest that the CTAB reacted with the halloystite to form a sealing layer on the surface of the nanotubes, thus encapsulating the solvent, while this was not verified using sodium polyacrylate.