Effect of Polyvinylpyrrolidone on the Morphologies of Latex Films and Air Permeability of the Latex Finished Fabrics

Low air permeability is a common problem happening to the coating finished and pigment dyed fabrics.To tackle the problem,styrene and butyl acrylate copolymer latex was prepared and used as substitute for the binder.Then,polyvinylpyrrolidone(PVP)was fed into the latex.It was expected that pores could form in the resulting latex film after being rinsed.The morphologies of the latex films were analysized by scanning electric microscope(SEM).It was found that the continuity of the latex films decreased greatly because of the addition of PVP,leading to the loss of the stress at break of the films.After rinsing with methanol aqueous solution,PVP was easily leached off and(macro)void was formed in the latex films.The size of the void decreased with the increase of the PVP concentration.Then,the latex with and without PVP was used to finish the cotton fabrics and engaged as binder in pigment dyeing.After PVP was rinsed out,the air permeability of the fabrics improved greatly,which recovered to that of the unfinished one.In the meantime,the color fastness to rubbing was little affected.So,the method of PVP addition could be termed as an efficient way to improve the air permeability in coating and dyeing industry.

Preparation of Latex Film with Macropores and Their Applications in Pigment Dyeing

Aiming at improving the permeability of the pigment dyed fabrics,two kinds of hydrophilic polymers(polyvinyl pyrrolidone(PVP),and polyethylene glycol(PEG)were fed into the styrene-butyl acrylate(St-BuA)copolymer latex binder respectively to prepare films with macropores.The effects of the post-added polymers on the latex film formation process and film structures were studied and the performance of the dyed fabrics was evaluated.It was found that the drying process could still be divided into three stages even after the addition of PVP and PEG.And the water evaporation rate during the first and last stage remained the same as usual.However,after the addition of PVP,the onset of the second stage was delayed to high volume fraction,and PVP formed into spherical dispersion phase with 300 nm in diameter.It provided a great deal of interface between the latex polymer and the PVP phase,which led to an increase in the water evaporation rate during the second stage.A different case was found after the feeding of PEG.Firstly,the first stage ended at low volume fraction and a decreased evaporation rate was observed in the second stage.Secondly,the PEG dispersion appeared as finger-like structure in the transmission electron microscopy(TEM)images with 9μm in length.After rinsing,pores were found only in the films formerly containing PVP or PEG,and the shapes and the sizes were closely correlated with the initial morphologies of the PVP or PEG domains.However,the shade of color,the abrasion fastness,and the permeability of the dyed fabric were independent of the type of the post-added hydrophilic polymer.

Study of bulk morphology of polymer latex films using laser confocal fluorescence microscopy

Unlabeled poly(methyl methacrylate) (PMMA) and polystyrene (PSt) latex particles as well as covalently fluorescent dye labeled PMMA latex particles (FPMMA) were prepared by emulsifier free emulsion polymerization and dispersion polymerization, respectively. The surface and bulk morphology of the polymer latex mixture (FPMMA/PMMA or FPMMA/PSt, weight ratio: 1/99) filmed by evaporation at room temperature was studied by laser confocal fluorescence microscopy (LCFM). It was concluded from the LCFM images that labeled PMMA domains obviously coagulated in PSt matrix not only on the surface but also in the inner layers of the latex film. Furthermore, PMMA was richer in the middle layers but poorer on the surface layer or the layers near to the substrate for the polymer latex films.

EFFECT OF PARTICLE SIZE ON THE FILMING PROCESS OF POLYSTYRENE LATEX STUDIED BY AFM

The film formation process of micro-PS particles (diameter 742 nm) and nano-PS particles (diameter 29 nm) was studied by atomic force microscopy and differential scanning calorimetry. During a step heating process, the particles were annealed for 0.5 h at each selected temperature. It was found that the deformation and interdiffusion temperatures of the micro-PS particles are ca. 120-130degreesC and 140-150degreesC, that of the nano-PS particles are 90degreesC and 100-110degreesC respectively. The DSC traces of nano-PS particles showed that there was an exothermic peak near T-g after annealing for 0.5 h at the selected temperatures below 90degreesC; otherwise, the exothermic peak disappeared after annealing at 100degreesC or above. Compared with the micro-PS particles, the sintering process of nano-PS particles occurs at much lower temperature determined by the confined state of polymer chains with higher conformational energy in nano-particles, and completes in a much narrower temperature range driven mainly by the larger total surface energy.

EFFECT OF THE PHASE STRUCTURE EVOLUTION ON THE PROPERTIES OF FILMS FORMED FROM PBA/P(St-co-MMA) COMPOSITE LATEX

A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA)) were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(T_g)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/P(S...

PREPARATION AND PROPERTIES OF SILICONE-ACRYLATE COPOLYMER LATEX

Silicone-acrylate copolymer latex was prepared through three different polymerization processes, i.e., the batch process, preemulsified monomer addition and the monomer addition process. The results revealed that the monomer addition process is a desirable approach to produce narrow particle size distribution latex with higher polymerization conversion and less amount of coagulum. The effect of silicone content on the glossiness and water absorption of latex film was investigated and the results showed that the glossiness of latex film is improved up to a silicone content of 10% of total monomers, but becomes impaired thereafter, whereas water absorption is reduced accordingly.

B4C/NRL flexible films for thermal neutron shielding

Boron carbide/natural rubber latex(B_4 C/NRL)flexible films were prepared via dip-molding with B_4 C content in the range of 5–55 wt% for thermal neutron(0.0253 e V) shielding. B_4 C was well dispersed in NRL according to microscopic observation. Both the inside and outside surfaces of the film were smooth. For B_4 C/NRL flexible films, the minimum elongation at break was greater than 600%, the minimum tensile strength was greater than 12 MPa, and the hardness was in the range of 35–55 HA,which were suitable for preparing flexible wearable products. The attenuation efficiencies of the B_4 C/NRL flexible films for thermal neutrons were also calculated. The B_4 C/NRL flexible films exhibit good attenuation effect for thermal neutrons.

Preparation and characterization of Bi2O3/XNBR flexible films for attenuating gamma rays

A bismuth oxide(Bi_2O_3)-dispersed carboxylated nitrile butadiene rubber(XNBR) flexible film was prepared as a flexible lead-free material for gamma ray(c-ray)attenuation.However,obtaining a uniform and stable dispersion of Bi_2O_3 in carboxylated nitrile butadiene rubber latex(XNBRL) is a challenge due to sedimentation induced by the remarkable density differences.Here,this challenge was approached by reducing the Bi_2O-3 particle radius,increasing the viscosity of the latex,and adding a dispersant.The experimental results confirmed that Bi2 O3 was well dispersed in the XNBRL in the concentration range of 30–70 wt%.The mechanical properties demonstrated that the Bi_2O_3/XNBR flexible films had a good resistance to oil,acid,alkali,and hot air.The linear attenuation coefficients of the Bi_2O_3/XNBR flexible films obtained from the experiments were in good agreement with the calculated values.The attenuation efficiencies of the Bi_2O_3/XNBR flexible films with different thicknesses and Bi_2O_3 contents were investigated for a few different γ-ray energies.These results showed that the Bi_2O_3/XNBRflexible films have wide application prospects for low-energy γ-ray attenuation.

白炭黑补强天然胶乳胶膜性能的提升研究

采用白炭黑对天然胶乳胶膜补强,并通过正交试验研究硫黄、促进剂PX、碳酸锌、白炭黑用量对硫化胶膜物理性能的影响。结果表明:以硫化胶膜的拉伸强度为考察指标,4个因子的影响从大到小依次为促进剂PX、白炭黑、碳酸锌、硫黄,优化用量为促进剂PX0.9份、白炭黑1.11份、碳酸锌0.6份、硫黄1份,相应配方硫化胶膜的拉伸强度可达到31.37 MPa;以硫化胶膜的撕裂强度为考察指标,4个因子的影响从大到小依次为白炭黑、促进剂PX、硫黄、碳酸锌,优化用量为白炭黑1.31份、促进剂PX0.7份、硫黄1.25份、碳酸锌0.5份,相应配方硫化胶膜的撕裂强度可达到65 kN·m^(-1)。

天然胶乳薄膜与木棉纤维/聚酯纤维非织造布吸声复合材料的制备与性能研究

天然胶乳薄膜具有独特的粘弹性和阻尼特性,木棉纤维具有大中空的独特结构,两者均可作为吸声材料基材。通过将木棉纤维与中空聚酯纤维混合后采用针刺加固工艺制成非织造布,然后直接与天然胶乳薄膜复合,制备天然胶乳薄膜与木棉纤维/聚酯纤维非织造布吸声复合材料,研究天然胶乳薄膜层数、复合材料面密度、木棉纤维/聚酯纤维质量比、复合材料孔径等对复合材料吸声性能的影响并分析复合材料的力学性能。结果表明:在天然胶乳薄膜层数为2、复合材料面密度为1215.72 g·m^(-2)、木棉纤维/聚酯纤维质量比为6/4、复合材料孔径为109.5μm时,天然胶乳薄膜与木棉纤维/聚酯纤维非织造布吸声复合材料的综合性能最优,最大吸声系数可达到0.8;与天然胶乳薄膜复合可弥补木棉纤维/聚酯纤维非织造布在低频率区域吸声效果的不足,有效拓宽复合材料的吸声频带,拓展其应用领域。

环氧树脂乳化剂的合成及其乳液的性能评价

以环氧树脂E-44为主要原料制备了水性环氧乳液。研究了乳化剂掺量对乳液粒径特征、贮存稳定性和离心稳定性的影响,并测试了最佳乳化剂掺量下乳液胶膜的基本性能。结果表明:随着乳化剂掺量的增加,乳液微粒逐渐向粒径更小的方向迁移,贮存稳定性与离心稳定性均逐渐提升。当乳化剂掺量大于18%时,乳液平均粒径减小幅度与稳定性提升幅度均放缓,推荐乳化剂掺量为18%~24%。乳化剂掺量为18%时的乳液胶膜固化后铅笔硬度为3 H,柔韧性为1 mm,附着力为1级,具有较好的耐水耐酸性。

内墙乳胶漆抗开裂性能的研究

研究分析了云母粉、滑石粉、煅烧高岭土、成膜助剂对内墙乳胶漆漆膜遮盖性能、开裂性能及其他性能的影响。结果显示,在控制原料成本的前提下,当滑石粉和煅烧高岭土的用量分别为8.0%和12%时,产品能够符合GB/T 9756—2018优等品的遮盖性能;与蓬松煅烧高岭土相比较,层状结构的煅烧高岭土更有助于改善漆膜的开裂性能;当成膜助剂的添加量为1.2%时,漆膜的低温成膜性能和耐沾污性均较为理想。通过以上优选解决方案,既可改善内墙乳胶漆的开裂性能,又能控制原料成本,最终提高客户满意度。

含氢聚甲基硅氧烷/丙烯酸丁酯/羟甲基丙烯酰胺复合乳液的研究——原料配比对乳液及胶膜性能的影响

采用含氢聚甲基硅氧烷（ＰＨＭＳ）与丙烯酸酯类单体进行接枝共聚，制得兼具二者优异性能的新型ＰＨＭＳ／丙烯酸丁酯（ＢＡ）／羟甲基丙烯酰胺（ＮＭＡ）复合聚合物乳液．讨论了ＰＨＭＳ、ＮＭＡ和引发剂用量对该复合乳液的聚合反应转化率、稳定性及粘度的影响．采用透射电子显微镜和粒度测试仪对不同反应条件下制备的乳液的粒度进行了测定．同时对聚合反应的机理、产物的结构及胶膜性能作了考察．结果表明：通过乳液聚合，得到了ＰＨＭＳ／ＢＡ／ＮＭＡ共聚物，控制ＰＨＭＳ、ＮＭＡ、引发剂等用量可制得粒度和粘度适中，具有较高转化率的稳定ＰＨＭＳ／ＢＡ／ＮＭＡ复合聚合物乳液。

VAE/PA乳液共混体系研究

对乙烯－醋酸乙烯共聚物（ＶＡＥ）乳液与丙烯酸酯共聚物（ＰＡ）乳液共混体系的稳定性、流变性及乳胶膜力学性能进行研究，结果表明，适量的非离子型乳化剂加入对共混体系的稳定性有明显作用。共混乳液表观粘度随剪切速率的增加而减少。共混乳胶膜力学性能对共混乳液的组成有很大依赖关系，当ＶＡＥ／ＰＡ在７０／３０左右时共混乳胶膜具有较大的屈服强度及拉伸强度。适当的增容剂加入乳胶膜力学性能有明显提高。以ＤＳＣ及ＴＥＭ研究共混乳胶膜的热行为及微观结构表明共混体系具有一定的相容性。

印刷纸张用苯丙水性上光油的研制

采用苯乙烯、甲基丙烯酸甲酯、丙烯酸丁酯等为单体,吸取微乳液聚合和无皂乳液聚合的一些特点,以非预乳化的半连续加料方式加料,合成出苯丙共聚物乳液。研究了PH调节剂、后续单体滴加时间以及保温反应时间等工艺条件对乳液及乳胶膜性能的影响。结果表明,所制得的乳液的单体转化率、乳液固含量和凝胶率分别为95.31%、42.66%和0.41%;乳胶膜的光泽度达到94.8%,吸水率为19.2%,乳胶膜的硬度、柔韧性和附着力俱佳。

氨基硅氧烷改性水性聚氨酯及其乳胶膜的性能

以异佛尔酮二异氰酸酯、聚四氢呋喃二醇、二羟甲基丙酸和三羟甲基丙烷(TMP)等为原料合成了内交联的水性聚氨酯预聚体,用3-氨基丙基三乙氧基硅烷(KH550)进行封端改性,乳化后进一步水解缩合交联,得到了高交联度的水性聚氨酯。采用傅里叶变换红外光谱、热重分析和X射线衍射技术对水性聚氨酯的结构进行了表征,并测试了乳胶膜的力学性能和耐介质性。实验结果表明,合成预聚体的较佳条件:n(—NCO):n(—OH)=1.4、—COOH质量分数1.8%(基于水性聚氨酯)、TMP质量分数1.0%(基于水性聚氨酯);当KH550质量分数(基于水性聚氨酯)由0增至10.0%,乳胶膜的拉伸强度由18 MPa增至28 MPa,吸水率由17%降至8%,吸乙醇率由46%降至30%以下。表征结果显示,KH550上的—NH_2与水性聚氨酯的端—NCO发生反应,实现了化学改性;KH550使乳胶膜的耐热性明显提高;随KH550含量的增加,乳胶膜的结晶度下降。

非离子型水性环氧树脂乳化剂的制备及其乳液性能的研究

以环氧树脂E51为母体,聚乙二醇为表面活性基团,合成了非离子型乳化剂,并通过相反转法制备了环氧乳液。探讨了乳化剂用量对乳液的粒径及其分布、稳定性的影响,并考察了其固化膜的性能。结果表明,随乳化剂用量增加,乳液的粒径减小,分布变窄,贮存稳定性与离心稳定性均增强。当乳化剂用量达到21%(以环氧树脂质量为基础)时,乳液的粒径减小至1.45μm;在3 000 r/min,30 min的条件下离心稳定性良好,密封贮存6个月不分层。乳化剂用量为24%时所制乳液在室温下固化7 d后所得胶膜的微观结构致密,铅笔硬度3H,附着力1级,柔韧性1 mm,冲击强度15 kg·cm,耐水性、耐酸性和热稳定性良好。

单分散聚苯乙烯乳胶有序膜在二氧化硅多孔材料制备中的模板作用

A method for preparing 3D ordered macroporous silicate materials was developed by using the ordered stacking structure of monodispersed polystyrene latex as a template. By using a modified sol\|gel procedure, the ordered template was permeated and filled with silicate, and the title porous materials was formed after removing the template by calcination at high temperature. Moreover, the pores were highly ordered throughout all the sample. After observing the morphological profile of the sample before calcination, it was found that silicate existed in two typical morphologies: monodispersed particles in the cavities and interconnected network within the interstice of the template. The transition morphology was rod\|like formed by the condensation of the silicate monodispersed particles. Two aspects concerning with the template effects of the ordered latex film were emphasized: the polymeric spheres may result in orderly packed holes after calcination, and the dielectric interfacial layer surrounding the polymeric spheres may induce the formation of monodispersed silicate spheres with ordered stacking. Both aspects played important roles in the formation of the highly ordered inorganic porous materials by calcination the gel at high temperature.

复合聚合物乳液性质的研究

用３种不同的加料方法和两种不同的加料顺序，制备了ＰＡＮ／ＰＢＡ复合聚合物乳液。测定了聚合物乳胶粒子的大小和分布；检测了聚合物乳胶的表面张力、电导率、流变性、离心和电解质稳定性，以及乳胶膜的光泽度、耐水耐溶剂性、力学性能；同时进行了差示扫描量热分析。探讨了聚合方法－成核机理－粒子微观结构－乳胶性质之间的关系。研究发现，全滴加法乳胶粒径最小，导电率小，表面张力大，电解质和离心稳定性高；乳胶膜的光泽度，柔软性和耐水性好；但拉伸强度差，丙烯腈后加法中，膜的力学性能最差。

颜料颗粒的分散状态聚丙烯酸酯/铜酞菁蓝复合乳胶膜中颜料颗粒的分散状态

功能颗粒存在下,水性胶乳在织物、纸张、皮革等目标基质表面的焙烘成膜是众多生产领域中普遍存在着的一个固化成型过程。通常认为功能颗粒在乳胶膜内初级粒子形式的均匀稳定分散可赋予涂层最佳的功能性和黏结牢度[1]。但目前常见的、