Poly(2-Hydroxyethyl Methacrylate-Bis[Trimethoxysilylpropyl]Amine) Hybrid Networks

In this paper, our goal is to improve the understanding of structural control of hybrid materials synthesized by using acid-catalyzed sol–gel reactions of bis-[trimethoxysilylpropyl]amine (BisSi) and 2-hydroxyethyl methacrylate (HEMA) via free radical in a common solvent. Polymer networks compositions were determined by FTIR and ¹H-NMR spectroscopy. The thermal properties of the P(HEMA-BisSi) hybrids with different silica content (e.g. 10, 15 and 25 wt%) were determined by thermogravimetric analysis and differential scanning calorimetry. Glass transition temperatures (T_g´s) of P(HEMA-BisSi) networks were also compared with T_g of PHEMA homopolymer. The T_g´ of PHEMA homopolymer was found as 103.74 °C. The thermal stability of these networks was increased with the BisSi content. Scanning electron microscopy images showed that an increase in acid content caused a decrease in the pore size and pore volume as well as in the surface area of the xerogel.     

Synthesis and Evaluation of β-Cyclodextrin–2-Hydroxyethyl Methacrylate Copolymer as a Novel Adsorbent

2-Hydroxyethyl methacrylate (0·01mol) was allowed to react with 0·01mol of hexamethylene di-isocyanate and the product was coupled to 0·01mol of β-cyclodextrin to form a new cyclodextrin-based copolymer. The interaction of the polymer with different steroids was investigated and the extent of adsorption was in the order cholesterol>progesterone>testosterone. The results indicate that the new polymer matrix could be used for the removal of steroids, particularly cholesterol, from a given medium. The polymer could also be used for sample purification, such as the removal of progesterone from a mixture prior to its analysis by other analytical techniques. The preliminary results show that the polymer may have interesting clinical and analytical applications. © of SCI.     

Preparation and Mechanical Characterization of Gelatin-Based Films Using 2-Hydroxyethyl Methacrylate Cured by UV Radiation

Gelatin films were prepared from gelatin granules in aqueous medium by casting. Tensile strength, tensile modulus and elongation at break of the gelatin films were found to be 27 MPa, 100 MPa and 4%, respectively. Gelatin films were soaked in five different formulations containing 2-hydroxyethyl methacrylate (HEMA) (10–50%, by wt), methanol and photoinitiator and then cured under UV radiation. Again, a series of gelatin solutions was prepared by blending varying percentages (10–50% by wt) of HEMA and then films were prepared and UV cured. It was found that tensile properties of gelatin films improved significantly.     

Relaxation Behaviour of Poly(2-Hydroxyethyl Acrylate) and of Its Copolymers with 2-Hydroxyethyl Methacrylate

Abstract

The molecular mobility of poly(2-hydroxyethyl acrylate) (PHEA) and of its copolymers with 2-hydroxyethyl methacrylate (H EM A) was determined by means of dynamic mechanical measurements with a torsional pendulum. The low-temperature dispersion assigned to the motion of the hydroxyethyl groups of the side chains was observed at -133°C (1 Hz) for all polymers; its intensity increased with the content of HEMA. Another secondary dispersion of PHEA detected at -95°C(1 Hz) was ascribed to the motion of the side chains including oxycarbonyl groups. With the incorporation of HEMA the temperature of the latter dispersion remained virtually unchanged, but its intensity rapidly decreased. The main transition temperature of PHEA, T_a = 9°C (1 Hz) is lower than T_a of PHEMA by approximately 94°C; the effect of the copolymer composition on T_a could be described by means of a one-parameter equation. The sorption of water led to a significant decrease in the T_a of PHEA and to an intensification of the secondary relaxation process.     

Mechanical behavior of masonry materials at high temperatures

An experimental campaign is presented to determine the effects of high temperatures on the mechanical properties of several materials for masonry walls (blocks and mortars), testing a series of cylindrical specimens (diameter of 100 mm and height of 200 mm). After compression tests at 20 °C, an experimental procedure was designed for high‐temperature testing. The cylindrical samples were heated in a muffle furnace, then were inserted into a specific apparatus (called ‘thermos’) for maintaining the prescribed temperature, and finally were subjected to a mechanical compression test. The results obtained by applying this procedure show a common variation of the strength, reduction of modulus of elasticity, and corresponding increments of the ultimate strain with temperature enhancement. Specific diagrams and discussion on the results are performed for each material. Copyright © 2014 John Wiley & Sons, Ltd.     

Mechanical and Dynamic Mechanical Properties of Photocrosslinked Norbornene-Thiol Copolymer Films

A number of novel organic norbornene and norbornene siloxane polymer precursors have been synthesized as part of an on-going research project to produce a non-acrylate, UV-curable adhesive system. These precursors (monomers or oligomers) are di-, tri- and tetra-functional. The crosslinking agent is a multifunctional thiol.

The organic norbornene systems, formulated to stoichiometry, have been characterized using thermal, static and dynamic mechanical analysis. We have found that norbornene ester systems have a range of physical properties, with tensile moduli ranging from 820-2300 MPa (118-350 kpsi), tensile strengths of 17-61 MPa (2.5-8.8 kpsi) and elongations of 4-100%. Glass transition temperatures range from 30-71°C for samples cured at room temperature with a dose of 620 mJ/cm².

Norbornene siloxanes crosslinked with thiol siloxanes have been formulated with increasing levels of a high surface area reinforcing agent. Tensile properties of filled films show that filler loading to 30 wt% significantly increases peak stress and elongation to break above that of 25 wt% filler. The addition of filler did not appear to increase the T_g of the films in this series monotonically. Increased levels of filler were found to produce films with a broadened cold crystallization range and an increased melting temperature.     

The Mechanical Behaviour of Polyimide/Copper Laminates Part 2: Peel Energy Measurements

The mechanical peel behaviour of laminates consisting of polyimide films adhered to copper foil using a modified acrylic adhesive has been studied over a wide range of test rates and temperatures. The laminates were prepared from polyimide films which had been subjected to either a “high-thermal history” or a “low-thermal history” treatment during the production of the film. The measured peel energies of the laminates could be superimposed to give a master curve of peel energy versus the reduced rate of peel test, Ra_T , where R is the rate of peel test and a_T is the time-temperature shift factor. The appropriate shift factors were a function of the test temperature and were mainly deduced from tensile tests conducted on the bulk adhesive. The “high-thermal history” laminates gave higher peel energies and the locus of failure of the laminates was mainly by cohesive fracture through the adhesive layer. At low values of log₁₀ Ra_T , i.e. Low rates of peel and high test temperatures, the “low-thermal history” laminates also failed in the adhesive layer and possessed similar peel energies to those measured for the “high-thermal history” laminates. However, at high log₁₀ Ra_T values, the peel energies measured for the “low-thermal history” laminates were lower and showed a wider scatter. These arose from a different locus of failure occurring in these “low-thermal history” laminates when tested under these conditions. Namely, it was found that most of these laminates failed in a weak boundary layer in the outer regions of the “low-thermal history” polyimide film.     

The Mechanical Behaviour of Polyimide/Copper Laminates Part 2: Peel Energy Measurements

The mechanical peel behaviour of laminates consisting of polyimide films adhered to copper foil using a modified acrylic adhesive has been studied over a wide range of test rates and temperatures. The laminates were prepared from polyimide films which had been subjected to either a “high-thermal history” or a “low-thermal history” treatment during the production of the film. The measured peel energies of the laminates could be superimposed to give a master curve of peel energy versus the reduced rate of peel test, Ra_T, where R is the rate of peel test and a_T is the time-temperature shift factor. The appropriate shift factors were a function of the test temperature and were mainly deduced from tensile tests conducted on the bulk adhesive. The “high-thermal history” laminates gave higher peel energies and the locus of failure of the laminates was mainly by cohesive fracture through the adhesive layer. At low values of log₁₀ Ra_T, i.e. Low rates of peel and high test temperatures, the “low-thermal history” laminates also failed in the adhesive layer and possessed similar peel energies to those measured for the “high-thermal history” laminates. However, at high log₁₀ Ra_T values, the peel energies measured for the “low-thermal history” laminates were lower and showed a wider scatter. These arose from a different locus of failure occurring in these “low-thermal history” laminates when tested under these conditions. Namely, it was found that most of these laminates failed in a weak boundary layer in the outer regions of the “low-thermal history” polyimide film.     

1-(2-羟乙基)-4-(2-羟丙基)哌嗪基复合胺脱硫剂的合成与性能

以哌嗪(PZ)、环氧乙烷(EO)、环氧丙烷(PO)为原料,以水为溶剂,PZ先与EO反应后中间产物再与PO反应合成1-(2-羟乙基)-4-(2-羟丙基)哌嗪基复合胺脱硫剂.在PZ初始浓度为0.1 g/mL H2O,PZ:EO:PO摩尔比为1:0.8:1.2,PZ与EO、PO的反应温度分别为35℃、25℃,中间产物与PO在反应时间为150 min的优化条件下,所得复合胺脱硫剂成分为1-(2-羟乙基)-4-(2-羟丙基)哌嗪、N,N′-二(2-羟丙基)哌嗪、N-(2-羟乙基)哌嗪、N-(2-羟丙基)哌嗪、N,N′-二(2-羟乙基)哌嗪、N-(1-甲基-2-羟乙基)哌嗪和哌嗪,其对气体SO2的饱和吸收量为0.7218 mol/mol,解吸率为98.37％.     

Phase Behavior and Mechanical Properties of Siloxane-Urethane Copolymer

Two series of siloxane-urethane copolymers were prepared from polydimethylsiloxane (PDMS) with a molecular weight of 1000 or 1800 which was used as a soft segment, 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (1,4-BD). Differential scanning calorimetry (DSC) demonstrated that the position (T_gs) and breadth (ΔB) of soft-segment glass transition of copolymers remained constant as the hard-segment content increased. Heat capacities at soft-segment glass transition of the copolymer (ΔCp) were 0.195∼0.411 J/g^○C and heat capacities of pure PDMS (ΔCp₀) were 0.571∼0.647 J/g^○C, leading to the various ΔCp/ΔCp₀ ratios. The ΔCp/ΔCp₀ ratios decreased as the increasing of hard-segment content, showing poor phase separation. The FTIR spectrum confirmed the occurrence of hydrogen bonding in ether end-group of pure PDMS. The ether group of the soft segment led to interfacial mixing between soft and hard segments. The tan δ of the soft segment determined by dynamic mechanical testing (DMA) also identified the mixing of soft and hard segments. The mechanical properties of the copolymer were directly related to either the soft and hard segment contents or the chain lengths of soft and hard segments. The hard segment that reinforced the soft segment and interfacial thickness between soft and hard segment dominated the mechanical properties.     

聚氨酯接枝聚丙烯酸共聚物网络的合成与性能表征

介绍聚氨酯接枝聚丙烯共聚物网络的合成与性能表征。利用异氰酸酯封端的聚氨酯预聚物同丙烯酸／丙烯酸羟丙酯共聚物反应得到了聚氨酯接枝聚丙烯酸共聚物网络。用利叶变换红外光谱表征了网络的化学组成，用应力－应变实验测试了本聚合物网络的力学性能，用动态粘弹谱以及差示扫描量热法研究了随着ＰＵ与ＰＡ链段比例的改变，该交联体系相结合的变化。     

聚甲基丙烯酸甲酯／不饱和聚氨酯共聚物的力学性能

报道了ＰＭＭＡ／ＵＳＰＵ共聚物的力学性能。研究结果表明，ＵＳＰＵ对ＰＭＭＡ具人显著的增韧必增强作用。共聚物的模量－组成关系符合Ｄａｖｉｅｓ模型，表明共聚物中ＰＭＭＡ相和ＵＳＰＵ相之间呈互为连续的形态。     

Engineering Interpenetrating Polymer Networks of Poly(2-Hydroxyethyl Acrylate) as Ex Vivo Platforms for Articular Cartilage Regeneration

A hydrogel based on interpenetrating polymer networks (IPNs) has been designed to act as a platform in an articular cartilage bioreactor for the ex vivo test of scaffolds, simulating the host tissue. Poly(2-hydroxyethyl acrylate) (PHEA) has been mechanically reinforced by its interpenetration with poly(ethyl acrylate). The resulting IPNs are phase separated systems with a porosity that increases with the amount of PHEA. Compression Young's modulus decreases and permeability increases when increasing the PHEA content in the samples, being the IPN with a 79% of PHEA the best candidate to mimic articular cartilage.     

含氟丙烯酸酯共聚物乳液的制备及性能研究

以丙烯酸全氟辛基乙酯为主要单体,采用乳液聚合法制备了含氟丙烯酸酯共聚物,通过红外光谱和激光粒度分析对共聚物进行了表征,测试了共聚物乳液的稳定性,研究了单体含量和交联剂对共聚物性能的影响,测定了共聚物于皮革表面的防水、防油性能,并对共聚物乳液处理的皮革表面进行了SEM分析。结果表明,含氟丙烯酸酯共聚物乳液防水等级9级,防油等级6级,具有良好的低表面性能。     

N-(2-羟乙基)-2-噁唑烷酮的合成及应用

通过均匀设计实验,二乙醇胺与碳酸二甲酯反应合成了硼酸酯键合剂中间体N-(2-羟乙基)-2-噁唑烷酮;用SPSS软件处理实验数据,确定了合成N-(2-羟乙基)-2-噁唑烷酮收率与各反应因素的回归方程。得到其最优反应条件为碳酸二甲酯与二乙醇胺摩尔比:1.3∶1,催化剂甲醇钠的质量占二乙醇胺质量的0.50%,反应温度60℃,反应时间60 min;在该条件下,N-(2-羟乙基)-2-噁唑烷酮收率达98.2%。以N-(2-羟乙基)-2-噁唑烷酮和二乙醇胺共混合成的硼酸酯键合剂(BEBA)以相同的工艺和配方应用于5 L丁羟四组元推进剂装药实验,结果显示:推进剂常温、高温各项力学性能指标均高于发动机设计要求15%,高温黏附指数φ为1.02,其综合力学性能优于醇胺类键合剂LAB-303B、二乙醇胺硼酸酯键合剂BAG-5及海因三嗪类键合剂BA603。     

松香季戊四醇酯与甲基丙烯酸-2-羟乙酯反应研究

松香季戊四醇酯（RPE）环上的共轭双键可以与甲基丙烯酸-2-羟乙酯（HEMA）发生Diels-Alder加成发应,同时松香季戊四醇酯仍有一定酸值,其中未反应的羧基可与HEMA进行酯化反应。研究了反应温度和物料配比对RPE与HEMA反应的影响,对产物进行了红外和热重分析。结果表明：在一定的物料比下,反应温度升高,加成反应和酯化反应速度加快,反应温度提高更有利于酯化反应的进行;在一定的反应温度下,HEMA的物质的量增加,产物的酸值到一定程度不再下降,而溴值持续下降,表明有利于HEMA与RPE的加成反应。红外光谱表明将HEMA接到了RPE的分子结构上,热重分析表明产物的初始分解温度和最终分解温度有所下降。     

天然橡胶接枝甲基丙烯酸羟乙酯的合成与表征

以甲基丙烯酸羟乙酯(HEMA)为接枝单体,过氧化二苯甲酰(BPO)为引发剂,合成了天然橡胶(NR)接枝聚甲基丙烯酸羟乙酯(NR-g-HEMA)。研究了BPO和HEMA用量、反应温度、反应时间以及NR塑炼时间对单体转化率、接枝率和接枝效率的影响,并采用红外光谱对接枝产物进行了表征。结果表明:当BPO用量为3%,HEMA用量为30%,反应温度为80℃,反应时间和NR塑炼时间分别为4h和30min时,NR-g-HEMA的接枝率达16%。     

GAP共聚体系静态力学性能研究

利用 GAP与 BAMO/ THF、PTE、PEG共聚以改善其网络结构 ,所得弹性体力学性能有不同程度提高。尤其在 GAP/ PTE、GAP/ BAMO中 ,当共聚组分重量比相近时 ,δ、ε达到最佳。通过 DSC考察相容性发现只存在一个玻璃化转变区 ,两种聚醚以嵌段共聚的形式共同形成交联网络。     

2-羟乙基吡啶的常压合成研究

研究了以2-甲基吡啶和多聚甲醛常压催化合成2-羟乙基吡啶的方法。从反应类型和机理出发,分析了在反应过程中不同性质的催化剂的影响;然后根据推论,采用酸碱两类催化剂,并对其催化效果分析比较,发现碱性催化剂三乙胺,更有利于2-羟乙基吡啶合成;探讨了催化剂量、反应比例、反应时间等影响因素,得出了适宜的反应条件:n(2-甲基吡啶)∶n(甲醛)=5∶1,在三乙胺催化下,反应时间40 h,反应收率85.2%,产物纯度可达99.0%,水分低于1.0%。     

3＇－（双－2－羟乙基）氨基苯甲酰苯胺的研制

以间硝基苯胺为原料，经苯甲酰化、铁粉还原和羟乙基化等反应合成了３＇－（双－２－羟乙基）氨基苯甲酰苯胺，并对反应的影响因素进行了讨论。