Research on Ventilation and Heat Insulation Layer Design of Split-Type Roof Greening Based on Topological Interlocking Principle

In this paper,the roof ventilation and heat insulation layer modules are combined with the roof greening,and each module is assembled through the principle of topological interlocking.The assembly of these modules does not require any rivets or cement mortar,and the structural stability of the overall assembled roof is achieved only through the interlocking and limiting the movements of the interlocked units.The green roof designed in this paper has strong applicability and can be applied to roofs of different shapes.Such a roof can not only meet the aesthetic needs,but also beautify the urban environment and reduce carbon emissions.

Carbon foams prepared from coal tar pitch for building thermal insulation material with low cost

A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.

Sound absorption and insulation property of closed-cell aluminum foam

The closed-cell aluminum foams (specimenρ=0.31 g/cm3, diameter of 100 mm, and thickness of 20 mm for sound absorption testing; specimenρ=0.51 g/cm3, length of 1 240 mm, width of 1 100 mm, and thickness of 30 mm for sound insulation testing) were prepared by the method of molten body transitional foaming process. Its sound absorption property under frequency of 160-2 000 Hz and the sound insulation property under frequency of 100-4 000 Hz were tested. The sound absorption results show that the sound absorption property is much better under middle frequencies than that under low and high frequencies. The sound absorption coefficient climbs when frequency increases from 160 Hz to 800 Hz and then drops when frequency is increased from 800 Hz to 2 000 Hz. The function of the sound absorption mainly depends on the Helmholtz resonator, the microphone as well as cracks of closed-cell aluminum foam. The sound insulation experiments show that the sound reduction index (R) is small under low frequencies, and large under high frequencies; the weighted sound reduction index (Rw) and the highest sound reduction index (R) can reach around 30.8 dB and 43 dB, respectively.

Lightweight Si_(3)N_(4)@SiO_(2) ceramic foam for thermal insulation and electromagnetic wave transparency

Increasing porosity is one of the most direct ways to improve the thermal insulation and dielectric properties of materials.Until now,many wet methods for preparing Si_(3)N_(4) ceramic foams usually face the problems of complex rheology,long period,and expensive cost,and the reported pore sizes of Si_(3)N_(4) ceramic foams are typically micron-grade,resulting in a lack of competitiveness in thermal insulation and wave-transparent applications.In this paper,the Si_(3)N_(4)@SiO_(2) ceramic foams were prepared using an efficient dry-method,which combined three processes of low temperature chemical vapor deposition(LTCVD),template,and isostatic pressing.The method has the advantages of simple operation and short preparation period,and can realize near-net size molding and mass production.In addition,the evolution mechanisms of honeycomb microstructure and composition of Si_(3)N_(4)@SiO_(2) ceramic foam during sintering were studied by chemical reaction thermodynamics.The as-prepared Si_(3)N_(4)@SiO_(2) ceramic foam possesses low density(0.377 g·cm^(-3)),high compressive strength(7.5 MPa),low thermal conductivity(0.0808 W·m^(-1)·K^(-1)),and excellent dielectric properties(ε<1.32,tanδ<0.009)in the frequency range of 8-18 GHz,and its maximum working temperature in air can reach up to 1100℃.It will be recommended to be applied in the interlayer of Si_(3)N_(4) ceramic radome to improve its thermal insulation and electromagnetic wave transparency performances.

Multifunctional cellular carbon foams derived from chitosan toward self-cleaning, thermal insulation, and highly efficient microwave absorption properties

To adapt the practical demand,designing and constructing the multifunctional microwave absorbers(MAs)is the key future direction of research and development.However,effective integrating the multiple functions into a single material remains a huge challenge.Herein,cellular carbon foams(CCFs)with different porous structures were elaborately designed and fabricated in high efficiency through a facile continuous freeze-drying and carbonization processes using a sustainable biomass chitosan as the precursor.The obtained results revealed that the thermal treated temperature and g-C_(3)N_(4) amount played a great impact on the carbonization degrees,pore sizes,and morphologies of CCFs,which led to their tunable electromagnetic(EM)parameters,improved conduction loss,and polarization loss abilities.Owing to the special cellular structure,the designed CCFs samples simultaneously displayed the strong absorption capabilities,broad absorption bandwidths,and thin matching thicknesses.Meanwhile,the as-prepared CCFs exhibited the strong hydrophobicity and good thermal insulation,endowing its attractive functions of self-cleaning and thermal insulation.Therefore,our findings not only presented a facile approach to produce different porous structures of CCFs,but also provided an effective strategy to develop multifunctional high-performance MAs on basis of three-dimensional CCFs.

Preparation of Magnesia Insulation Materials by Walnut Shell Powder Impregnated with Silica Sol

In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregates(using high purity magnesia powder as starting material and potassium oleate as the foaming agent),middle grade magnesia powder,calcium aluminate cement,and SiO_(2) micropowder as starting materials,introducing walnut shell powder impregnated with silica sol(short for Sws)as a pore-forming agent.The effects of the Sws addition(0,10%,15%,and 20%,by mass)and the sintering temperature(1300,1350,1400,and 1480℃)on the properties of magnesia insulation materials were studied.The results show that(1)for the specimens fired at 1480℃,when the Sws addition is 10%,the cold compressive strength is 22 MPa;when the Sws addition is 20%,the thermal conductivity is 0.368 W·m^(-1)·K^(-1)(350℃);(2)nano-silica in the silica sol reacts with MgO in the matrix to form forsterite,which encapsulates the pores volatilized from the walnut shell powder and forms closed pores.

3D打印隔热材料研究进展

3D打印技术能够实现面向性能的设计以及非常规结构的制造,其在隔热领域的应用可以使材料具有更加精细、可控、定制化的结构与功能。当前,3D打印隔热材料技术仍处于快速迭代期,打印材料、结构设计和制造工艺等技术瓶颈尚待突破。本文对3D打印隔热材料的现状进行了综述,简要分析了在隔热材料制造方面较有前景的3D打印工艺,对比了各工艺的优缺点以及适用的材料类型,着重讨论了3D打印陶瓷、发泡混凝土、泡沫塑料和气凝胶材料在隔热领域的研究进展,最后总结了目前面临的技术挑战和未来的主要发展方向。

聚合物基隔热泡沫材料的制备及其研究进展

以聚合物为基体的多孔材料即聚合物泡沫材料具有比强度高、隔热优良、质量轻、隔音性能好、性价比高等优势。简述了聚合物基隔热泡沫材料的制备方法的发展历史。对聚合物泡沫材料的导热机理进行了归纳,汇总了近些年聚合物基隔热泡沫材料的相关研究,概述了聚合物基泡沫材料结构与导热性能之间的关系。分析了目前常用隔热泡沫材料制备方法的优缺点,指出超临界流体发泡技术由于环保、无毒等优点被广泛应用在隔热聚合物泡沫材料的制备中,且可通过调整温度、压力和外场等对泡孔的尺寸、发泡倍率等进行调控。

基于钒钛磁铁矿尾矿的发泡陶瓷制备及性能研究

攀西地区铁尾矿的大量堆积严重污染了当地的生态环境。固废基发泡陶瓷吸波材料在解决铁尾矿堆积问题的基础上,推进了发泡陶瓷在吸波材料领域的应用。通过正交试验探索了烧结温度、保温时间和发泡剂掺量对发泡陶瓷物理性能的影响,并综合分析得出优选烧结方案:烧结温度为1190℃,保温时间为60 min,发泡剂掺量为质量分数0.3%。依照此方案制备的发泡陶瓷体积密度为0.23 g/cm^(3),体积吸水率为0.76%,抗压强度为0.73 MPa,导热系数为0.06 W/(m·K),孔隙率为89.89%。在正交试验制定的工艺基础上,探索了试样厚度对发泡陶瓷吸波性能的影响。研究结果表明:在烧结温度1170℃,吸波剂掺量为质量分数30%时,厚度为15 mm的发泡陶瓷吸波性能最优,在0.5~18 GHz的频率范围内反射损耗降低至-28.58 dB,显示出2.35 GHz的有效吸收带宽。该研究为钒钛磁铁矿尾矿的资源化利用和发泡陶瓷在吸波材料方面的运用提供了参考。

二氧化硅气凝胶原位填充聚酰亚胺泡沫的结构及隔热性能研究

以超轻质开孔柔性聚酰亚胺泡沫为基体,采用溶胶凝胶工艺制备了一系列二氧化硅气凝胶原位填充的聚酰亚胺复合泡沫。复合泡沫密度10~100 kg/m^(3)可调,厚度1~400 mm可调,最大宏观尺寸可达1m×1m。对其泡孔结构、隔热性能、热性能进行了系统表征,分析了二氧化硅气凝胶原位填充聚酰亚胺泡沫的隔热机理。结果表明:二氧化硅气凝胶的引入,可有效降低复合泡沫室温热导率,提高其隔热性能;随着二氧化硅气凝胶含量的增加,聚酰亚胺复合泡沫的热导率由38.8 mW/(m·K)降低至19.6 mW/(m·K);热端温度300℃时,复合泡沫热导率仅为61.1 mW/(m·K);填充二氧化硅气凝胶后,聚酰亚胺复合泡沫热稳定性大大提高,在900℃下热失重残留量约为80%。

烧成温度对钙长石隔热耐火材料显微结构与性能的影响

本工作以矾土水泥与黏土为原料,采用发泡法制备了钙长石隔热耐火材料,通过XRD、SEM和导热仪等分析了烧成温度(1110~1310℃)对钙长石隔热耐火材料显微结构与性能的影响,并研究了该种钙长石隔热耐火材料的合成机理。结果表明:当烧成温度为1110~1160℃时,体系内开始生成钙长石,但原料微颗粒间的反应并不完全,生成的液相含量较少,强度较低;当烧成温度为1210~1260℃时,液相含量增多,钙长石的生成速度加快,强度增大,试样具有较低导热系数;当烧成温度为1310℃时,液相含量迅速增多,线收缩率迅速增大,试样具有较大强度,但体积密度大幅增长,气孔率降低。在1260℃时,制得了体积密度为0.53 g/cm^(3)、气孔率为82.6%、抗折强度为1.15 MPa、耐压强度为1.99 MPa、800℃导热系数为0.101 W/(m·K)的钙长石隔热耐火材料。

气凝胶隔热材料在水泥行业的应用

详细介绍了气凝胶隔热材料的制备工艺、隔热机理,对比了新型气凝胶隔热材料与传统隔热材料的性能优势;结合新型气凝胶隔热材料在水泥行业的应用案例,具体分析了气凝胶隔热材料在水泥回转窑、分解炉、冷却系统、烧成系统辅助设备中的应用。新型高效的气凝胶隔热材料将逐步取代传统保温隔热材料,建立新型热防护系统,减少能源消耗,进一步推动水泥行业的节能降碳绿色转型。

Development of sustainable thermal insulation based on bio-polyester filled with date pits

Date palm pit(DPP)-filled poly(-hydroxybutyrate)(PHB)composites were prepared,evaluated,and characterized to determine their thermal insulation ability.Thermal conductivity values ranged between 0.086 and 0.100 W/(m·K).At a maximum filler concentration(50%(w)),the specific heat capacity and thermal diffusivity were 1183 J/(kg·K)and 0.0689 mm^(2)/s,respec-tively.The DPP increased the thermal stability,and the highest compressive strength obtained was 80 MPa at 30%filler content.The PHB-DPP composites exhibited promising water absorption(less than 6%)and tensile strength(6-14 MPa).Date-pit-based PHB composites could be used in sustainable building engineering and cleaner production.

膨胀聚苯乙烯颗粒泡沫混凝土结构设计与应用

基于导热系数和抗压强度设计原则,从膨胀聚苯乙烯颗粒优选、水泥基复合胶凝材料硬化基体优化、微孔化、固体相体积占比等方面考虑,研究了不同干表观密度膨胀聚苯乙烯颗粒泡沫混凝土(PFC)的导热系数和抗压强度,通过配合比优化,实现了PFC结构性能、导热系数和抗压强度三者的协调;采用优化后的配合比,可制备出综合性能较佳的建筑保温与结构一体化墙体砌筑材料。

团体标准《绿色设计产品评价技术规范家具用软质聚氨酯泡沫塑料》介绍和解读

综述了软质聚氨酯泡沫的绿色产品设计的必要性和相关产品标准现状,介绍了团体标准T/CNLIC 0089—2023《绿色设计产品评价技术规范家具用软质聚氨酯泡沫塑料》内容和技术细节。

绿色节能保温硬泡聚氨酯板制备及粘接强度与性能测试

为研究绿色建筑节能保温硬泡聚氨酯板制备及剪切粘接强度性能测试,通过混合一定比例的聚醚多元醇与固化剂等原料制备建筑节能保温硬泡聚氨酯板,在不同影响因素下测试剪切粘接强度性能。结果表明,硬泡聚氨酯板制备陈化时间为1440 min时,可有效保障其导热系数稳定、可靠,加工密度宜保持在57.5~60 g/m^(3),聚醚二元醇、三元醇的配比以1∶1、3∶2为宜,此时剪切粘接强度与断裂伸长率均较高,在浸水、紫外线老化、冻融循环环境下,随着粘接面积的增长,硬泡聚氨酯板的剪切粘接强度呈上升趋势,说明制备的硬泡聚氨酯板节能保温和剪切粘接强度性能较好。

碱激发铁尾矿泡沫混凝土的制备及其性能

为了资源化利用铁尾矿,以铁尾矿、粉煤灰、矿渣为原料,通过碱激发胶凝材料部分替代水泥制备泡沫混凝土,分析了碱激发胶凝材料、泡沫、水胶比、聚乙烯醇等对泡沫混凝土抗压强度和导热系数的影响,并利用电镜扫描、X射线衍射分析其微观结构及反应机理。结果表明,当碱激发胶凝材料掺量为40%、水胶比为0.40、聚乙烯醇为1%时,28 d最大抗压强度为4.99 MPa,干表观密度为784 kg/m^(3),导热系数为0.1909 W/(m·K),满足规范要求。

建筑保温用掺聚丙烯纤维发泡水泥制品的力学性能

为改善包裹聚苯乙烯颗粒发泡水泥保温材料的力学性能,在基础配方工艺上额外掺加聚丙烯纤维,并分析发泡水泥保温材料采用不同掺加方式、掺加不同质量分数聚丙烯纤维后的力学性能差异。研究结果表明:聚丙烯纤维的最佳掺加方式为先掺法,纤维质量分数为0.8%时保温材料的力学性能达到最佳值;掺入最佳质量分数聚丙烯纤维后发泡水泥保温材料养护3、28 d的抗折强度分别提升至0.31、0.53 MPa,3、28 d的抗压强度分别提升至0.48、1.03 MPa。

超低能耗建筑外墙聚氨酯空腔发泡保温施工技术

传统超低能耗建筑外墙保温基本为无机、有机板材复合外保温系统,施工过程中质量不稳定,系统主要问题包括空鼓、开裂、饰面层脱落、渗漏、细部节点出现热桥等。以在建项目工程为案例,深入介绍了超低能耗建筑外墙聚氨酯空腔发泡保温系统施工工艺及无热桥施工技术,归纳了外墙聚氨酯空腔发泡保温技术的施工应用要点及注意事项,总结了聚氨酯空腔发泡外墙保温技术优势,旨在改进超低能耗建筑外墙施工技术,在满足建筑节能要求的前提下,降低成本,加快推进超低能耗建筑高质量发展。

废弃聚氨酯硬泡的回收再利用研究

以废弃聚氨酯硬泡为原料,研究了降解条件对降解效果的影响以及降解产物对开孔型聚氨酯硬泡性能的影响。具体考察了醇解剂、胺解剂、催化剂对硬泡溶解能力和产物特性的影响,以及再生多元醇的羟值、用量对泡沫开孔率和尺寸稳定性等的影响。结果表明:使用固体酸催化并采用先醇解后胺解的方式可有效降解板材废泡,降解所得再生多元醇的羟值为550~800 mgKOH/g,用量占组合聚醚质量分数的10%~40%时,可获得性能优良的开孔型聚氨酯硬泡。