Synthesis and characterization of novel elastomeric poly(D,L-lactide urethane) maleate composites for bone tissue engineering

Here, we report the synthesis and characterization of a novel 4-arm poly(lactic acid urethane)-maleate (4PLAUMA) elastomer and its composites with nano-hydroxyapatite (nHA) as potential weight-bearing composite. The 4PLAUMA/nHA ratios of the composites were 1:3, 2:5, 1:2 and 1:1. FTIR and NMR characterization showed urethane and maleate units integrated into the PLA matrix. Energy dispersion and Auger electron spectroscopy confirmed homogeneous distribution of nHA in the polymer matrix. Maximum moduli and strength of the composites of 4PLAUMA/nHA, respectively, are 1973.31 ± 298.53 MPa and 78.10 ± 3.82 MPa for compression, 3630.46 ± 528.32 MPa and 6.23 ± 1.44 MPa for tension, 1810.42 ± 86.10 MPa and 13.00 ± 0.72 for bending, and 282.46 ± 24.91 MPa and 5.20 ± 0.85 MPa for torsion. The maximum tensile strains of the polymer and composites are in the range of 5–93%, and their maximum torsional strains vary from 0.26 to 0.90. The composites exhibited very slow degradation rates in aqueous solution, from approximately 50% mass remaining for the pure polymer to 75% mass remaining for composites with high nHA contents, after a period of 8 weeks. Increase in ceramic content increased mechanical properties, but decreased maximum strain, degradation rate, and swelling of the composites. Human bone marrow stem cells and human endothelial cells adhered and proliferated on 4PLAUMA films and degradation products of the composites showed little-to-no toxicity. These results demonstrate that novel 4-arm poly(lactic acid urethane)-maleate (4PLAUMA) elastomer and its nHA composites may have potential applications in regenerative medicine.     

氨酯化合物对聚碳酸1,2-丙二酯的同时增韧和增强研究

采用非异氰酸酯路线合成了1,6-六亚甲基二氨基甲酸羟异丙酯(BPU),分子量为320.利用熔融共混方法制备了聚碳酸1,2-丙二酯(PPC)/BPU共混物.研究发现BPU与PPC间有较好的相容性,随着BPU含量的增加,共混体系的起始热分解温度(Td.5％)可分别增加24～33℃,共混物韧性也显著提高,断裂伸长率最大可增至...     

高分子造纸助剂的设计及作用机理研究Ⅱ.用XPS解析N-氯代聚丙烯酰胺与水和醇的反应

用X 射线光电子能谱仪 (XPS)对聚丙烯酰胺的部分N 氯代衍生物 (简称N 氯代聚丙烯酰胺 )与水、1 丙醇的反应产物进行了表征 .实验结果表明 ,在弱碱性水溶液中N 氯代聚丙烯酰胺 (N Cl PAM)的N 氯代酰胺基的 93%转化成—CONHCONH—结构 ,而在 1 丙醇水溶液中 ,91 8%的N 氯代酰胺基转化为—CONHCONH—和—NHCOO—结构 ,二者比例为 78 0∶13 8.可以推论N Cl PAM在中性造纸条件下 ,可通过自身结合形成网络结构或与纤维羟基反应形成共价键 ,从而达到增强纸的干、湿强度效果     

Synthetic methods for polyamine linkers and their application to combinatorial chemistry

Summary Polyamines and polyamine conjugates display a diverse range of important biological functions, ranging from antibiotics to immunosuppressants and glutamate receptor antagonists. For these reasons, polyamines provide an excellent template/scaffold for combinatorial chemistry. In this paper we present methods for the solid-phase immobilisation of polyamines for use in synthetic and combinatorial chemistry and describe how they have been employed in the preparation of a number of important polyamine conjugates and polyamine libraries. Thus, we have designed, synthesised and utilised a number of polyamine linkers for both solution and resin screening combinatorial application.     

氨酯丙烯酸酯树脂的合成及其固化反应动力学研究

用不同分子量的聚氧化丙烯二元醇合成了一系列氨酯丙烯酸酯齐聚物（ＵＡＯ）以及含硬段／软段结构的ＵＡＯ，并用ＦＴ－ＩＲ跟踪了这类ＵＡＯ的合成过程。通过ＵＡＯ的链端双键测定，以及ＧＰＣ、ＶＰＯ测定的分子量，表征了ＵＡＯ的数均官能团度。进一步通过ＦＴ－ＩＲ研究了由ＵＡＯ与甲基丙烯酸甲酯形成的氨酯丙烯酸酯树脂（ＵＡＲ）固化时的共聚反应动力学，发现其共聚反应速率与体系中的扩散效应密切相关。在这类ＵＡＯ中引入硬段后，共聚合体系呈现出反常的动力学行为，与网络结构形成过程中材料的形态发展有关。     

THE CRYSTALLIZATION BEHAVIOR OF URETHANE SUBSTITUTED POLYDIACETYLENE

The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness of lamellae is about 300A, being independent of the crystalline temperature. But the size and density of lamellae were dependent on the crystallization temperature. If the molten film was sheared during the crystallzation process the oriented lamellae grew with their long axes perpendicular to the direction of shear and the chain direction was normal to the lamellar surface.     

Kinetic and computational studies on aminolysis of bicyclic carbonates bearing alicyclic structure giving alicyclic hydroxyurethanes

Aminolysis of bicyclic carbonates, which consist of five-membered cyclic carbonate and five- or six-membered alicyclic groups, was examined. Kinetic studies revealed that the aminolysis of the bicyclic carbonate with cyclohexane ring proceeded more smoothly than that of the bicyclic carbonate with cyclopentane ring. Computational calculation suggested that the different reaction rates originate from the distinct ring-strain of the cyclic carbonate groups affected by the conformation of the alicyclic groups.     

Synthesis of urethane acrylates modified by linseed oil and study on EBC coatings

In this paper, five different structural urethane acrylates modified by linseed oil were synthesized and then properties of their electron beam cured (EBC) coatings, i.e., adhesion, gloss, flexibility, impact resistance, hardness, tensile strength and elongation were studied. It was shown that these synthesizing conditions of urethane acrylates modified by linseed oil were temperate. Effect of structure of urethane acrylates modified by linseed oil on these properties of their EBC coatings was obvious, except gloss. According to synthetical properties of EBC coatings, the optimum oligomer among these was No. A, whose main chains were formed by hexane diacid, average functionality was 2, and oil content was 25.5%. With increasing of absorbed doses, these properties of EBC coatings, except gloss, changed correspondingly. It was advisable that absorbed dose wasn’t greater than 180 kGy. At higher absorbed doses, cobaltous naphthenate had obvious effect on these properties of EBC coatings, whose oil content of linseed oil was rather high.     

How to reveal latent degradation of coatings provoked by UV-light

This paper deals with predictions of the service life of the two main technologies used for automotive clearcoats: acrylic-melamine and acrylic-urethane. This work demonstrates that the UV-light irradiation leads to chain scissions and crosslinking for the unstabilised and stabilised formulations. Mechanisms are proposed to explain the dramatic increase in the values of the mechanical properties for the two technologies as a function of the ageing time. For a determined critical value of the mechanical properties, water acts to reveal the latent damage by leading to the formation of cracks. Moreover, when the polymer reaches a certain level of network densification due to UV-light irradiation, the system cannot accept the stress induced by the water inflation/deflation and cracks will occur. Other solvents were also tested to understand the effects of polarity on the formation of the cracks.     

二苯基碘鎓盐引发乙烯基醚热聚合研究

合成了一种液态聚氨酯乙烯基醚预聚物 (PUE)并对其进行了表征 .研究发现二苯基碘六氟磷酸盐(PI810 )能够引发PUE和三缩乙二醇二乙烯基醚 (DVE 3)进行阳离子热聚合 ,热聚合温度远低于PI810的纯态热分解温度 ,且聚合转化率较高 .热聚合的机理初步认为是电子转移机理 .研究了乙烯基醚化合物、环氧树脂、二苯基碘六氟磷酸盐混合体系的热聚合 .